HLA-A and B antigens were studied in 88 Caucasoids with chronic pancreatitis resident in the Manchester area. In the subgroup of 52 patients with alcohol-related chronic pancreatitis HLA-B21 was significantly increased in frequency compared with 344 local controls (Pc = 0.0128). In the non-alcoholic sub-group of 36 patients, the incidence of HLA-A1 was significantly higher than in controls (Pc = 0.0021); whilst HLA-B8 was present in 38.8% of patients and 27.9% of controls. When these data are amalgamated with data from Lyon (France), the antigen HLA-A1 is significantly associated with non-alcoholic chronic pancreatitis.