Females of Chinese hamsters with spontaneous diabetes (CHAD), which have been developed as a genetic strain of type I diabetes, were mated with males of non-diabetic Chinese hamsters (CHA). According to the grade of glucose intolerance, the females of CHAD were divided into four groups, i.e. normal, chemical and diabetic group such as mild and severe group. In the diabetic groups, hyperglycemia in fetuses and in the severe group a significant high incidence of fetal abnormalities were observed. The lung phospholipids of fetuses were analyzed. No changes in phosphatidylcholine content but a decrease in the percentage of its dipalmitoyl species was observed in the fetal lungs from the diabetic groups as compared to the normal group. Phosphatidylglycerol content was also found to be decreased in the severe group by the results of thin-layer chromatography and immunological semiquantification with an AmnioStat-FLM kit. These results of lipid analysis revealed that the diabetic pregnancy in this animal model showed typical feature of delayed fetal lung maturity. Therefore, this animal model should be useful for studying the mechanism of delayed fetal lung maturity as well as the development of respiratory distress syndrome in fetuses from dams with diabetes.