INTRODUCTION: Overweight patients sometimes present a practical problem for provision of lower-limb prostheses. Most information about the effect of body weight on the endurance of prostheses is based on laboratory tests. This is a retrospective study based on an audit to study the effect of body weight and age on the frequency of repairs. SUBJECTS: One hundred and sixteen patients were involved (98 male), age 16-96 years, mean=58.7 years; weight 47-140 kg, mean=88 kg; 68 were transtibial amputees and 48 were transfemoral amputees. Causes of amputation were trauma (49), peripheral vascular disease (29), and others (38). Amputation was done 1-66 years prior to assessment, mean=13.66 years. Period of use of current prostheses was 0.5-28 years, mean=3.5 years. RESULTS: One hundred and one repairs were done in a period of 6 months. The number of repairs was found to correlate significantly with weight (P value<0.001) and inversely with age (P value=0.003). No significant correlation was found between repairs and gender, cause of amputation, or level of amputation. CONCLUSION: Body weight and age of amputee are determining factors in the frequency of repairs of lower-limb prostheses. However, a larger study for a longer period will be needed to confirm our finding. [ABSTRACT FROM AUTHOR]