The importance of wound classification and site of ulceration was evaluated in 314 consecutive diabetic patients with foot ulcers. The ulcers were classified as superficial (through the full thickness of the dermis; n = 150), deep (n = 50), osteomyelitis and/or abscess (n = 46), minor gangrene (n = 39) or major gangrene (n = 29). Wound healing was defined as intact skin for at least 6 months. In patients with superficial and deep ulcers, primary healing occurred in 88% and 78%, respectively, compared with 57% in those patient who developed an abscess and/or osteomyelitis. Only 2 out of 68 patients with gangrene healed (through mummification) without amputation. Patients with gangrene had lower ankle and toe blood pressure than patients with all other types of ulcers. There were only marginal differences in primary healing rate between different ulcer sites. The highest rate was seen in ulcers localized to the metatarsal heads (78%). Patients with multiple ulcers had the lowest primary healing rate (5%) compared with single ulcers at all sites. These differences were probably due to circulatory factors, since patients with multiple ulcers had lower distal perfusion pressures compared with all other groups.