One hundred and three unrelated patients with Type 1 (insulin-dependent) diabetes were typed for HLA, properdin factor B (BF), glyoxalase 1 (GLO), Kidd blood group, and 24 other genetic markers. Observed distributions of marker phenotypes among these patients were compared with those expected according to population frequencies, in an attempt to detect associations between Type 1 diabetes and the markers. Strong associations between Type 1 diabetes and both HLA and properdin factor B were confirmed, as was a lack of association between Type 1 diabetes and glyoxalase (GLO). There was an apparent deviation from Hardy-Weinberg equilibrium at the GLO locus, and statistically significant distortions in the distributions of pancreatic amylase (AMY2), galactose-1-phosphate uridyl transferase (GALT), and group-specific component (GC) among Type 1 diabetes patients, but these results are not significant when corrected for performance of multiple tests. An increase in the Lewis-negative phenotype reported elsewhere was observed here but was not statistically significant. A distortion in the distribution of Kidd types reported elsewhere was not confirmed.