The evaluation of the safety and effectiveness of colistin in association with rifampin and imipenem in 1 diabetic patient with severe diabetic foot infection (DFI) due to multidrug-resistant (MDR) Pseudomonas aeruginosa, complicated by osteomyelitis, is presented in this "Case Report". The patient received colistin after other ineffective antimicrobial treatment when an MDR P aeruginosa strain was isolated by cultural examination, together with a multidisciplinary care approach including surgical debridement and adequate offloading. The efficacy of combination colistin plus rifampin plus imipenem was observed with a checkerboard method and bactericidal activity of the serum. The patient received colistin combination therapy for 6 weeks with cure of the infection and without renal toxicity. These data suggest that colistin, in combination with rifampin and imipenem, is safe and effective, in promoting healing in DFI due to MDR P aeruginosa and suggest the need for controlled clinical studies.