Bennett fractures are unstable, and, with inadequate treatment, lead to osteoarthritis, weakness and loss of function of the first carpometacarpal joint. This study focuses on long-term functional and radiological outcomes after open reduction and internal fixation. Between June 1997 and December 2005, 24 patients with Bennett fractures were treated with open reduction and internal fixation with screws at our center. Radiological and functional assessments including range of motion of the thumb and pinch and grip strength were performed 4months post-procedure and at the long-term follow-up, on average 83months after surgery. Reduction of the Bennett fracture was maintained as it was at the time of the procedure in 96% of the cases when fixation with two lag screws was performed. At the 4-month follow-up, mean pinch and grip strength reached 92±3 and 89±4% of the contralateral side, respectively. Long-term follow-up demonstrated no correlation between the accuracy of the fracture reduction and the development of post-traumatic arthritis. Good clinical results could be observed, if successful reduction of the fracture was achieved and maintained. However, there was no correlation between the accuracy of the fracture reduction considering a gap and step <2mm and the development of arthritis.