This paper summarizes the results of a multi-year research project investigating the occurrence and control of atrazine and its degradation products in drinking water supplies. Major portions of the research results are described in detail in a series of reports. The results of a study of the reaction of atrazine with ozone have been described and are briefly summarized herein. Other portions of the research results have not been previously published. The objectives of this research effort were: To document the types and concentrations of atrazine degradation products present in raw and conventionally treated drinking water supplies contaminated with atrazine (and to examine their occurrence relative to atrazine, which has been much more thoroughly studied); To determine the major byproducts formed, under a range of typical water treatment conditions, by the reaction of ozone with atrazine and its major degradation products; To examine the effectiveness of granular activated carbon (GAC) adsorption, powdered activated carbon (PAC) adsorption, and ion exchange for removal of atrazine and its degradation products; To examine the effectiveness of point-of-use GAC filters in removing atrazine over the stated lifetime of the filter; and To determine whether oxidants such as potassium permanganate, chlorine, and chlorine dioxide have any significant effect on atrazine or its degradation products.