suspended or reduced service due to COVID-19, had since reached out for either a resumption of service or an increase in frequency, up from 53% and 42% respectively through the second quarter. As a result, solid waste collection, transfer and disposal revenue was down 2.0% year over year on a same store basis in the third quarter, an improvement of 330 basis points from Q2, which was down 5.3% year over year.
The impact of the COVID-19 outbreak on our business, results of operations, financial condition and cash flows in future periods will depend largely on future developments, including the duration and spread of the outbreak in the U.S. and Canada, its severity, the actions to contain the novel coronavirus or treat its impact, and how quickly and to what extent normal economic and operating conditions can resume.
Q3 2020 Results
Revenue in the third quarter totaled $1.390 billion, as compared to $1.412 billion in the year ago period. Operating income was $230.7 million, which included $7.9 million of costs primarily resulting from impairments and other operating items and acquisition-related costs. This compares to operating income of $236.6 million in the third quarter of 2019, which included $13.4 million of costs primarily resulting from impairments and other operating items.
Net income attributable to Waste Connections in the third quarter was $158.0 million, or $0.60 per share on a diluted basis of 263.5 million shares. In the year ago period, the Company reported net income attributable to Waste Connections of $159.1 million, or $0.60 per share on a diluted basis of 264.6 million shares.
Adjusted net income attributable to Waste Connections* in the third quarter was $188.6 million, or $0.72 per diluted share, versus $192.9 million, or $0.73 per diluted share, in the prior year period. Adjusted EBITDA* in the third quarter was $432.6 million, as compared to adjusted EBITDA* of $443.6 million in the prior year period.
Adjusted net income attributable to Waste Connections, adjusted net income attributable to Waste Connections per diluted share and adjusted EBITDA, all non-GAAP measures, primarily exclude impairments and other operating items and acquisition-related items. For detailed reconciliations, please refer to the attached tables.
Nine Months Year to Date Results
For the nine months ended September 30, 2020, revenue was $4.048 billion, up from $4.027 billion in the year ago period. Operating income, which included $453.1 million of costs primarily related to the decrease in property, plant and equipment at certain E&P landfills as a result of the Company’s impairment testing, was $215.3 million, compared to $643.6 million for the same period in 2019, which included $44.7 million of costs primarily resulting from impairments and other operating items.
Net income attributable to Waste Connections for the nine months ended September 30, 2020, was $74.0 million, or $0.28 per share on a diluted basis of 263.7 million shares. In the year ago period, the Company reported net income attributable to Waste Connections of $433.6 million, or $1.64 per share on a diluted basis of 264.5 million shares.
Adjusted net income attributable to Waste Connections* for the nine months ended September 30, 2020, was $517.2 million, or $1.96 per diluted share, compared to $538.1 million, or $2.03 per diluted share, in the year ago period. Adjusted EBITDA* for the nine months ended September 30, 2020, was $1.235 billion, as compared to $1.255 billion in the prior year period.
Q3 2020 Earnings Conference Call
Waste Connections will be hosting a conference call related to third quarter earnings on October 29th at 8:30 A.M. Eastern Time. To access the call, listeners should dial 800-920-3365 (within North America) or 212-231-2902 (international) approximately 10 minutes prior to the scheduled start time and ask the operator for the Waste Connections conference call (a passcode is not required). A replay of the conference call will be available until November 5, 2020 by calling 800-633-8284 (within North America) or 402-977-9140 (international) and entering Passcode # 21969551. The call will be broadcast live over the Internet through a link on the Company’s website at www.wasteconnections.com. A playback of the call will be available on the Company’s website.
Waste Connections will be filing a Form 8-K on EDGAR and on SEDAR (as an "Other" document) prior to markets opening on October 29th, providing the Company's fourth quarter 2020 outlook for revenue, core price plus volume growth for solid waste and adjusted EBITDA*.
* A non-GAAP measure; see accompanying Non-GAAP Reconciliation Schedule