The third in a series of biennial conferences on progress in chemical disinfection was held in Binghamton, New York, April 3-5, 1986. The Conference was jointly sponsored by the State of New York Research Foundation Technology Transfer Office; Lonza, Inc; and the U.S. Environmental Protection Agency's Water Engineering Research Laboratory. The primary purpose of the Conference was to bring together researchers working on new disinfectants and disinfection concepts and those in the regulatory and industrial community to discuss progress and possible applications in solving water treatment problems. The proceedings of the conference are a compilation of the speakers' papers, poster session papers, transcripts of a panel discussion, and comments and questions expressed following each paper. Major topic areas included: advances in industrial applications of disinfectants, nonclassical and new chemical disinfectants, point of use water treatment, Giardia concerns, and two general sessions covering a variety of related topics. The proceedings will be of interest to all concerned with the potential for improved disinfection processes for drinking water.