BACKGROUND Complex patterns of impaired bone healing can result in a severe economic and social burden for the patient. Herein we describe the local application of recombinant human bone morphogenetic protein 7 (BMP-7). The goal of this prospective study is to review the indications, application and validation of this therapy. METHODS From June 2002 to June 2008, we applied 101 BMP-7 treatments in 101 nonunions of 98 patients. The average age of the patients was 50 years (18-88 years). The gender composition was 29 women (30%) and 69 men (70%). Before BMP-7 application, patients had already underwent surgical treatement an average of 3.3 times (median 3, 1- to 13-times). We used BMP-7 "off-label" in all long bones. RESULTS In 93 cases (92%), we observed proper bone healing. The average healing time was 4.8 months (range 1.5-11 months). The average time from injury to BMP-7 application was 18.4 months (3-84 months). In 65 cases, BMP-7 application was combined with re-osteosynthesis and autologous bone grafting. Serious side effects were not observed. CONCLUSIONS BMP-7 should not be used as general treatment of nonunion in all patients, but appears to be effective for the treatment of complex cases. In clinical practice, the decision to proceed with off-label use of BMP-7 should be made on a case-by-case basis.