DIANON Systems Elects New Director.

STRATFORD, Conn.--(BUSINESS WIRE)--June 3, 1997--Kevin Johnson, President and CEO, DIANON Systems, (NASDAQ:DIAN) announced today that E. Timothy Geary has been elected as a member of the Board of Directors.

Mr. Geary is Chairman, President and CEO of National Surgery Centers, Inc. of Chicago, Illinois, the leading independent owner and operator of ambulatory surgery centers in the country. Prior to founding National Surgery Centers, Mr. Geary served as a Vice President with Medical Care International. Mr. Geary is a member of the Board of Directors of the Federated Ambulatory Surgery Association. He received his Master of Business Administration and Bachelor of Arts degrees from the University of Chicago.

In making this announcement, Kevin Johnson said, "Tim brings to the DIANON Board vast experience in the provision of health care services. In addition to his demonstrated success in identifying market opportunities, he is leading a high growth company in a health care system that is undergoing rapid change. DIANON Systems will benefit greatly from Tim's insight as our anatomic pathology services continues its significant growth nationwide."

Jack Davis, Chairman of the Board, added, "The entire Board is delighted to have Tim join us. We look forward to having the benefit of his guidance in the continuing development of strategies to take advantage of the growth potential in DIANON's marketplace."

DIANON Systems, Inc. provides a full line of anatomic pathology testing services and a number of specialized genetic and clinical chemistry testing services to patients, physicians and managed care organizations throughout the United States.

CONTACT: DIANON Systems

Kevin C. Johnson, 203/381-4905