Vialog Contact: Mimi Englander
                                                         Asst. VP/Marketing
                                                         (978) 975-3700
                                                           menglander@vialog.com



FOR IMMEDIATE RELEASE



                      Vialog Corporation Names Kim Mayyasi
                      President and Chief Executive Officer

       -- Former Hill Holliday Executive Brings to the Company 20 Years of
           Telecom and Internet Marketing and Technology Experience --


Andover,  Mass.,  June 9, 1999 -- Vialog  Corporation  (NASDAQ:VLOG),  a leading
provider of  teleconferencing  services,  announced today the appointment of Kim
Mayyasi to the position of President and Chief Executive Officer, effective July
1, 1999.  Mr.  Mayyasi joins Vialog from Hill,  Holliday,  Connors,  Cosmopulos,
Inc.,  one of the  country's  top 25  advertising  agencies.  The  Company  also
announced that Glenn Bolduc has resigned as President and CEO.

"We are excited to have Kim join Vialog to guide the Company as it  continues to
expand its role in the  evolving  group  communications  market,"  stated  David
Lougee, a member of Vialog's Board of Directors.  "Kim's strategic  expertise in
the  telecommunications  and  Internet  markets  provides  the Company  with the
leadership necessary to pursue our objective of capitalizing on growth prospects
in both our core and Internet-based conferencing services."

"I am  delighted  to be joining the Vialog  team," said  Mayyasi.  "It is with a
great deal of  enthusiasm  that I look  forward to helping  Vialog  realize  its
potential in an emerging industry full of opportunity."

In 1991,  Mayyasi  founded  the MSP Group,  a marketing  technology  and service
company using  relational  databases,  artificial  intelligence  and  integrated
direct response services including telemarketing and fulfillment.  MSP Group was
acquired  by Hill  Holliday  in 1995,  at which time  Mayyasi  became a Managing
Partner at Hill Holliday, focusing on e-commerce marketing and technology.


                                   -- more --

Vialog Corporation Names Kim Mayyasi President and CEO - page two


Amassing 20 years of telecom  experience,  Mayyasi began his career at Satellite
Business  Systems,  where he designed and implemented a virtual private network.
He subsequently  became one of the key managers during the formation of Cellular
One Boston,  where he was vice  president of sales and  marketing.  Mayyasi also
co-founded Cellular One Portsmouth and its holding company Boston Communications
Group,  where he was general manager with P&L responsibility for Cellular One of
New Hampshire, Cellular Services of Washington, Beeper One and Cellular Express.

Mayyasi holds an MBA in Finance from  Thunderbird,  the American Graduate School
of  International  Management  and a BSEE from the  Massachusetts  Institute  of
Technology.

Mr.  Bolduc will assume a consulting  role with Vialog  through the end of 1999.
"We would  like to thank  Glenn for his  accomplishments  at Vialog  and for his
extraordinary efforts in organizing and forming the Company," stated Lougee.

"I found my work at Vialog to be some of the most  challenging  and rewarding in
my career,"  said Bolduc.  "I'm  looking  forward to  continuing  to support the
Company as it pursues its objectives."


About Vialog Corporation
Headquartered  in  Andover,  Massachusetts,  Vialog  is a  leading  provider  of
conferencing services, including audioconferencing;  videoconferencing; Internet
conferencing;  and automated  teleservices,  such as Interactive  Voice Response
(IVR),  MessageCast(sm)  voicemail  broadcast,  broadcast fax and fax on-demand.
Vialog helps  organizations  communicate  more  professionally,  efficiently and
effectively by delivering  superior  customer  service and an extensive range of
enhanced  and  customized   conferencing   solutions.   Vialog's   common  stock
(symbol:VLOG)   is  quoted  on  Nasdaq's   National  Market  System.   For  more
information, visit www.vialog.com.

                                      # # #

Statements in this press  release that are not based on historical  facts may be
considered  forward-looking  statements  that involve  risks and  uncertainties,
included but not limited to, the Company's  ability to successfully  implement a
strategy of continued  growth.  Factors that could cause or  contribute  to such
differences include, without limitation, changes in the market, new products and
announcements  from other  companies,  changes in technology,  and the impact of
competitive  products and pricing.  Additional  information  on the factors that
could  affect the  Company's  financial  results is  included  in the  Company's
amended  1997 Form  10-K and  other  Company  reports  which are filed  with the
Securities and Exchange Commission.