Thirty-one closed fractures of the lower extremity in diabetics were retrospectively reviewed to determine healing times. There was a prolonged union time overall (163% of expected) and in both insulin and oral hypoglycemic-controlled diabetics (157% and 176% of expected). Displaced fractures showed a prolonged union time, while nondisplaced fractures healed in the normal time period (187% and 96% of expected). Fractures treated by open reduction had a more prolonged healing time than those treated by closed reduction (186% and 142% of expected), but this was primarily related to displacement. Sex and age had no effect on union time. The known effects of diabetes mellitus on bone and mineral metabolism in both experimental animals and humans may explain these prolonged union times.