The aim of this study was to assess the results of percutaneous injection of autologous bone marrow in the treatment of fractures presenting with delayed union or non union after internal fixation. Twenty consecutive patients presenting to our outpatient clinic with internally fixed fractures with delayed union or non union were included in the study. The time between the index surgery and the bone marrow injection ranged from 4 to 24 months with a mean of 9.65 months. The bone marrow aspirate was injected percutaneously into the fracture site under fluoroscopy control. Nineteen out of the twenty fractures achieved clinical and radiological union, on average after 2.95 months. In this series, percutaneous bone marrow injection appeared as a simple and effective method to accelerate fracture healing in patients with delayed union and nonunion of fractures.