We analyzed 865 diarrheal outbreaks with an identified bacterial pathogen or unknown cause that occurred in the Israeli military between 1988 and 2002. The number of outbreaks per year declined over the study period, as did the proportion of outbreaks with an identified pathogen. Shigella, Salmonella, and Staphylococcus species were the bacteria most commonly isolated. Seventy percent of the outbreaks involved < 35 cases and only 5% involved > 100 cases. More than one-half of the outbreaks occurred in field units, but these outbreaks were smaller than those in other units. The most commonly identified cause of the outbreaks was a lapse in maintaining standards of food preparation. Improvements in infrastructure and enhanced attention to surveillance, education, and infection control have resulted in a marked decline in the number of outbreaks in recent years.