Retrospective cohort study. OBJECTIVES: To analyze characteristics and treatment of osteomyelitis (OM) in the treatment of grade IV pressure injury (PI) in patients with spinal cord injury/disorder (SCI/D) following the Basel Decubitus Concept. SETTING: Acute care and rehabilitation clinic specialized in SCI/D. METHODS: Patients with SCI/D were admitted for grade IV PI treatment between 1st January 2010 and 28th February 2015.Patients, SCI/D, and PI characteristics were collected from chart reviews. Descriptive statistics and differences between groups with and without OM were evaluated. RESULTS: In total, 117 patients (87 male, 30 female) with 130 PI grade IV were included. In 95 patients (81%), OM was diagnosed histologically. In 87 cases, more than one bacterial species was involved. Out of 49 different bacterial species, Enterococcus faecalis and Staphylococus aureus were most frequently observed. Amoxicillin/clavulanic acid and ciprofloxacin were the most frequently used out of 24 different antibiotics. Length of antibiotic treatment varied between <8 days and >91 days with 31 patients receiving antibiotics for about 8 weeks. Complications occurred in all groups of antibiotic duration. Having a paraplegia, no OM and sacral PI was associated with increased complication rates, but the number of patients did not allow comprehensive risk factor analysis. CONCLUSION: Because the variety of patients concerning SCI/D, PI, and OM characteristics did not show a conclusive relation between length of antibiotic treatment and complication rates, the development of a subgroup specific treatment concept for PI in patients with SCI/D would be favorable to further optimize antibiotic treatment.