OBJECTIVE To compare the results of using antegrade locked intramedullary nailing and the retrograde locked intramedullary nailing in the treatment of humeral shaft fractures. METHODS From January 1999 to December 2003, 92 closed humeral shaft fractures were operated with locked intramedullary nail. There were 92 patients, 67 men, 25 women, mean age 37 years (range 18 to 72 years). There were 69 antegrade nailing and 23 retrograde nailing. The average followup of the others was 28 months (12-70 months). RESULTS The difference between the two groups' operation time, union rate and Mayo elbow performance score were not statistically significant. However, there were statistic significance between the two groups' intraoperative complication rate and Constant-Murley shoulder score. CONCLUSIONS There is a much higher rate of iatrogenic fracture when retrograde nailing are performed. Antegrade nailing may influence the function of shoulder, but it's easier to manipulate.