Our goal was to estimate the occurrence rate of the post-initial remission and its relation with HLA phenotype in type I diabetics (DMI). We studied 50 type I diabetics, 22 women and 28 men, with an average age at the onset of the disease to 15.8 +/- years (range 3-30 years). All patients were conventionally treated with insulin therapy, diet and regular exercise. Six (12%) of the diabetics presented a complete remission during 57.3 +/- 46 weeks, whereas fifteen (30%) patients presented partial remission during 20.1 +/- weeks. No significant differences were observed with regard to age at the onset of the disease, sex, BMI, initial ketoacidosis and stage of gonadal development between those diabetics presenting remission and those who did not presented so. We observed a higher incidence of the HLA-DR4 antigen among diabetics with remission (complete and partial, 61.9%), compared with patients without remission (20%, p less than 0.5). In conclusion, our results support the findings suggesting the presence of a clinical-immunological heterogenicity in DMI, genetically determined and linked to the HLA system.