We report findings in 223 consecutively included people with diabetes, foot ulcer and a deep foot infection treated by a multidisciplinary diabetic foot care team at the University Hospital in Lund, Sweden. The aim of the present study was to evaluate type and characteristics of deep foot infections and their relation to choice of treatment and outcome. Three different groups of deep foot infections were identified; osteomyelitis only (n = 112), deep soft tissue infection only (n = 46) and combined infections (osteomyelitis and deep soft tissue infection, n = 65). The various types of deep foot infections had different characteristics, treatment and prognosis. Patients with a deep soft tissue infection only or a combined infection had a significantly (p < 0.05) higher; (1) body temperature (38.0 and 38.0 vs. 37.3 degrees C), (2) erythrocyte sedimentation rate (75 and 80 vs. 56 mm/h) and (3) white blood count (11.0 and 12.0 vs. 8 x 10(9)) at diagnosis compared with those who had osteomyelitis only. Patients with a deep soft tissue infection only or a combined infection also had a significantly (p < 0.05) shorter time to surgery (2 and 4 vs. 10 days), higher mean number of surgical procedures (1.9 and 2.1 vs. 1.4 procedures) and higher percentage of patients had intravenous antibiotics (87 and 84 vs. 46%) compared with those who had osteomyelitis only. Amputation before healing was more common in patients with a combined infection (62%) compared with those who had osteomyelitis only (37%) or a deep soft tissue infection only (30%). The findings in the present study indicate that deep foot infections in patients with diabetes is a heterogeneous entity, in which the type of deep foot infection is related to choice of treatment strategy and to outcome. Therefore, these various types of infections has to be considered in future studies of deep foot infections in people with diabetes.