The Turkish Association of Clinical Microbiology and Infectious Diseases, Diabetic Foot Infections Working Group conducted a prospective study to determine the factors affecting the outcomes of diabetic foot infections. A total of 96 patients were enrolled in the study. Microbiological assessment was performed in 86 patients. A total of 115 causative bacteria were isolated from 71 patients. The most frequently isolated bacterial species was Pseudomonas aeruginosa (n = 21, 18.3%). Among cases with bacterial growth, 37 patients (43%) were infected with 38 (33%) antibiotic-resistant bacteria. The mean (+/- SD) antibiotics cost was 2,220.42 (+/- 994.59) USD in cases infected with resistant bacteria, while it was 1,206.60 (+/- 1,160.6) USD in patients infected with susceptible bacteria (p < 0.001). According to the logistic regression analysis, the risk factors related to the growth of resistant bacteria were previous amputation (p = 0.018, OR = 7.229) and antibiotics administration within the last 30 days (p = 0.032, OR = 3.796); that related to the development of osteomyelitis was wound size > 4.5 cm(2) (p = 0.041, OR = 2.8); and that related to the failure of the treatment was the growth of resistant bacteria (p = 0.016, OR = 5.333). Diabetic foot osteomyelitis is usually a chronic infection and requires surgical therapy. Amputation is the accepted form of treatment for osteomyelitis. Limited limb-saving surgery and prolonged antibiotic therapy directed toward the definitive causative bacteria are most appropriate. This may decrease limb loss through amputations. As a result the infections caused by resistant bacteria may lead to a high cost of antibiotherapy, prolonged hospitalization duration, and failure of the treatment.