Three clusters of diarrheal illness occurred among patrons of two family-owned sushi restaurants in Reno, Nevada. Enterotoxigenic E. coli (ETEC) infections were identified in stools of patrons from two of the illness clusters. The third cluster of diarrheal illnesses was investigated. Multiple strains of ETEC were identified in six restaurant patrons and two employees. PFGE patterns for the isolates of the same serotype genetically matched each other. Two menu items were statistically associated with illness, tuna nigiri and upside down shrimp nigiri. Bivariate analysis indicated that butterfly shrimp, small scallops, tobiko, yellowtail fish, and hot chili sauce were associated with illness. All of these ingredients, except for the tuna and chili sauce, were included in the Upside Down Shrimp nigiri. With multivariate analysis of ingredients, butterfly shrimp was statistically associated with illness. The restaurants had poor sanitation and food handling practices. Employees reported diarrheal illness. There had been employee crossover between the two restaurants which could have contributed to the first illness cluster.