The polymorphism at the heat-shock protein gene was reported to be associated with type-1 diabetes in Caucasians but not in the Japanese. We report in this study the association between HSP70-1 alleles and type-1 diabetes in 30 unrelated African-American patients and 96 ethnically matched controls from the Washington, DC area. The polymorphic variation (A-C transversion) at position -110 in the HSP70-1 promoter region was amplified using the polymerase chain reaction. No significant differences between patients and controls were detected. These data suggest that in African Americans, HSP70-1 polymorphism is not associated with type-1 diabetes and is similar to findings in Japanese patients. The difference between results from this study and that of Caucasians may be due to population differences in genetic polymorphism or to linkage disequilibrium of HSP70-1 with human leukocyte antigen class-II alleles associated with type-1 diabetes susceptibility genes.