Rosetta Resources 8-K Regulation FD Disclosure

August 2008 ■Denver

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Forward Looking Statements

All statements, other than statements of historical fact, included in this presentation are “forward-
looking” statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and
Section 21E of the Securities Exchange Act of 1934, as amended, including statements regarding the
intent, belief or current expectations of Rosetta Resources Inc. and its subsidiaries (the “Company”) and
its management. These forward-looking statements are based upon current expectations and are subject
to a number of risks, uncertainties and assumptions that could cause actual results to differ materially
from those herein described. Accordingly, you are cautioned that these forward-looking statements are
not guarantees of future performance. Please refer to Company’s risks, uncertainties and assumptions as
it discloses from time to time in the Company’s reports and registration statements filed with the SEC,
including the risk factors identified in its Annual Report on Form 10-K for the year ended December 31,
2007, which can also be found on the Company’s website at www.rosettaresources.com.  The Company
undertakes no duty to update the information contained herein except as required by law.

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Corporate Profile

•Rosetta established as a stand-alone operating
company on July 7, 2005

•Stock trades on NASDAQ, symbol: “ROSE”

•Shares outstanding (Dil.)= 51.0MM

•Core areas include:

–Sacramento Basin

–DJ Basin

–Lobo

–Perdido

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It’s a Great Time to Look at Rosetta

•Track record of solid performance

–Strong financial and operational results

–Favorable cost structure

–Balance sheet capacity

•Quality asset base undergoing intensive evaluation to identify inventory
potential

•Plan in place for both growth and value creation

•Experienced management with passion and commitment

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Future business approach will focus on inventory
and program execution

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•Fully assess and identify inventory from existing assets

•Preference for organic growth from core unconventional assets

•Expect to extend existing assets into new opportunities and add new core
areas, as appropriate

•Pursue selective and opportunistic M&A

•Build and apply technology and operating expertise

•Focus on cost control

•Maintain financial flexibility

Balanced Plan for
Growth and Value Creation

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First Half 2008 Milestones

•Met or exceeded operational and financial expectations

•Implemented new organizational structure to focus on inventory and
execution

•Significant progress on hiring key talent

–Operations leadership in place

–Asset team structure implemented with staffing underway

–New Ventures team established with staffing underway

–Critical operations and staff functions staffed

•Existing asset inventory studies underway

•Acquired San Juan Basin properties from Petroflow

•Increased Borrowing Base to $400MM

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Record Financial Performance

2nd Quarter 2008

	2008	2007
Average Production (MMcfe/d)	155	120
Realized Price ($/Mcfe)	$10.96	$7.97
Total Revenues ($MM)	$154.5	$86.9
Total Cash Costs ($/Mcfe)	$2.31	$2.15
Net Income ($MM)	$39.3	$13.1
EPS Diluted ($/Share)	$0.77	$0.26

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Record Financial Performance

1st Half 2008

	2008	2007
Average Production (MMcfe/d)	153	114
Realized Price ($/Mcfe)	$10.13	$7.89
Total Revenues ($MM)	$282.8	$162.7
Total Cash Costs ($/Mcfe)	$2.27	$2.01
Net Income ($MM)	$66.8	$27.1
EPS Diluted ($/Share)	$1.31	$0.54
Debt/Total Capital	22%	22%

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Financial Flexibility to GrowLiquidity/Credit Capacity

•Revolving line of credit-conforming borrowing base of
increased to $400MM

•Currently have $245MM debt outstanding

•$229MM unused capacity

•Cash Balance $71MM at 6/30/08

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2008 Range: 140-150 MMcfe/d

Range

(MMcfe/d)

Record Production Growth

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($/Mcfe)

Improving Lifting Cost Performance

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2007

2006

Proved = 408 Bcfe

Proved = 418 Bcfe

(Bcfe)

Proved Reserve Base

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2007 Program1

Total CapEx = $334

2008 Budget Program

Total CapEx = $290

1) Includes OPEX Transaction at a cost of $39MM.

($MM)

2008 Capital Budget Reflects
Core Area Focus

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Core Areas

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“Grow Where Planted”	“Expansion Options”	“Transforming Options”
•Resource assessments in existing assets •Existing basin extensions, infill, and down spacing programs •Core up existing positions via lease acquisitions and small tactical acquisitions •Up to $30MM/deal	•New basin entry •Larger bolt-on transactions within existing core areas or to establish new core area •$30-$300MM/deal	•Partnerships and joint ventures •Larger company transactions •MOE’s •>$300MM/deal •Most likely a post-Calpine event

Inventory Capture Tactics

Comprehensive Approach to
Inventory Focus

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2008 Exploration Focus Areas

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General Info

•> 3.5 TCFE cumulative production (Rio Vista only)

•16 productive zones from 2,800’ to 12,500’

•> 75,000 net acres

•80 square mile of 3-D seismic

•83% average working interests

•> 180 producing wells

•Remaining Capital Inventory > 100 projects

2007 Activity

•Drilled 27 wells (85% success rate)

•Infill-drilled existing Martinez play

•Extended the areal extent of the Martinez play

•Successfully tested the Winters play

2008 Plans/Highlights

•Base Optimization

•Capital Focus

−Field development

−Field extensions

−Deep potential

•Identify & Evaluate Inventory / Resource Potential

* Average based on 6 months ending 12/31/05

Sacramento Basin

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* Average based on 6 months ending 12/31/05

DJ Basin

General Info

•Biogenic Gas Play (Niobrara Chalk)

•> 110,000 net acres

•125 square miles of 3-D seismic

•100% working interests

•Shallow drilling depths around 2,500 feet

•Remaining capital inventory > 500 new drills

2007 Activity

•Drilled 69 wells, 80% successful

•Completed pipeline infrastructure

2008 Plans/Highlights

•> 60 wells to be drilled

•Acquire additional 3-D seismic

•Acquire additional leasehold

•Focus on bolt-on acquisitions

•Identify & Evaluate Inventory / Resource Potential

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* Average based on 6 months ending 12/31/05

Lobo

General Info

•Tight Gas Play

•78,000 net acres

•320 square miles of 3-D seismic

•80% to 100% working interests

•Moderate drilling depths around 8,000 feet

•Remaining capital inventory > 100 new drills

2007 Activity

•42 wells drilled (79% success rate)

•Acquired > 10,000 net acres

•Acquired > 80 square miles of 3-D seismic

2008 Plans/Highlights

•> 48 wells to be drilled

•Acquire additional 3-D Seismic

•Acquire additional leasehold

•Identify & Evaluate Inventory / Resource Potential

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* Average based on 6 months ending 12/31/05

Currently drilling

Perdido Acreage

Perdido

General Info

•Horizontal Tight Gas Play

•9,000 net acres

•100 square miles of 3-D seismic

•50% working interest

•2500’ laterals at vertical depths of around 10,000 feet

•Remaining capital inventory > 70new drills

2007 Activity

•Drilled 1 vertical well

•Drilled 9 horizontal wells

2008 Plans/Highlights

•10 horizontal wells to be drilled

•Focus on lower CWC

•Acquire additional 3-D seismic

•Acquire additional leasehold

•Identify & Evaluate Inventory/Resource Potential

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San Juan Basin

Petroflow Acquisition

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	2007 Reserves (Bcfe)	2007 Production (MMcfe/d)
State Waters	10.3	2.7
Texas Other	14.1	4.7
Onshore Other	10.9	4.5
Gulf of Mexico	19.5	13.3
Total Other Assets	54.8	25.2
% of Rosetta Total	13%	20%

Other Asset Review

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Priorities for 2008:C-O-R-E

•Calpine Resolution

•Organization

–Fill key operations leadership roles

–Identify competencies and gaps

–Build essential operations and analytical functions

–Attract and retain quality workforce

•Resources

–Identify inventory in existing core positions

–Evaluate new basins and plays of interest

–Pursue M&A that makes sense

•Execution

–Focus on capital and cost efficiency

–Strive for differential performance

–Deliver on expectations

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Calpine Update

•Open Issues

–Non-Consent Properties ($75MM)

–Fraudulent ConveyanceResolution

•Recent Developments

–Calpine Emerged from Bankruptcy

–Report of Experts Received in March 2008

–Motion for Summary Judgment Pending

–Motion to Disqualify Calpine's expert filed (hearing on
August 27, 2008)

–Deposition Process Continuing

–Trial

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It’s a Great Time to Look at Rosetta

•Track record of solid performance

–Strong financial and operational results

–Favorable cost structure

–Balance sheet capacity

•Quality asset base undergoing intensive evaluation to identify inventory
potential

•Plan in place for both growth and value creation

•Experienced management with passion and commitment