Objective To analyze whether there are any gender differences in clinical features of acute type 1 diabetes mellitus.Methods Clinical data of 193 patients with acute type 1 diabetes mellitus were collected in our hospital from 2002 to 2007,and subjected to statistical analysis by SPSS.Results The ratio of male to female in all the subjects was 1.6:1.There was no significant gender difference in such clinical aspects as age,fasting blood glucose level,HbAlc concentration,positive percentage of serum autoantibodies against pancreatic islet or morbidity of diabetic neuropathy.In contrast to the males,the onset age was significantly younger,the diabetic duration longer,fasting serum C peptide level lower and the incidence of ketotic acidosis higher in female patients.The patients with onset age less than 14 years (puberty) did not show any significant gender differences in the above-mentioned clinical aspects.Among those with onset age more than 14 years,the females had significantly longer duration and lower fasting serum C peptide level than males.The male patients with onset age more than 14 years had significantly higher fasting serum C peptide level than those less than 14,whereas it was the same for total positive percentages of pancreatic islet autoantibodies and morbidity of diabetic neuropathy in females.Conclusion Gender differences may exist in some clinical features of type 1 diabetic patients with acute onset after puberty, which may partially result from the effects of sex hormones.