In this study, sera from 96 Sudanese patients with Type 1 diabetes and from 86 matched controls were tested for the following organ-specific antibodies: islet cell antibodies (ICA), thyroid microsomal antibodies (TMA), antithyroglobulin antibodies (ATA), and gastric parietal cell antibodies (PCA). In diabetic patients the prevalence rates of these antibodies were: ICA = 41.7%, ATA = 2.0%, TMA = 7.3%, PCA = 6.3%. All these rates were significantly higher than in controls except for ATA which showed similar low prevalence rates in patients and controls. The pattern of prevalence of these antibodies by age, sex, and duration of diabetes was assessed and compared with reports from other populations. The general pattern of these antibodies is similar to that reported in Caucasian populations, except for a slightly greater tendency for ICA to persist with increased duration of diabetes in our sample. Furthermore, the low prevalence of TMA in our population is comparable to that reported in Black American diabetic patients but significantly lower than rates reported in certain other racial groups.