The use of adductor pollicis muscle thickness (APMT) as a predictor of muscle and lean mass is not fully understood and little is known whether the APMT evaluation presents advantages when compared to simpler anthropometric measurements, such as body weight. We aimed to associate APMT, alone and plus body weight, with muscle mass and lean mass in kidney transplantation patients.A cross-sectional study was carried out with 129 kidney transplantation patients of both sexes that presented a high time of kidney transplant (95.6 ± 78.3 months). Body weight and height were performed and APMT was measured using a caliper. Lean mass and muscle mass were estimated by bioelectrical impedance.After linear regression analysis, APMT explained the variances of muscle mass and lean mass by 20% (R2 = 0.208; β = 0.456; p < 0.001) and by 26% (R2 = 0.264; β = 0.514; p < 0.001), respectively. Body weight predicted muscle mass by 21% (R2 = 0.216; β = 0.465; p < 0.001) and lean mass by 68% (R2 = 0.684; β = 0.828; p < 0.001). Analyzing weight plus APMT, the prediction of muscle mass and lean mass increased by 8% (R2 = 0.29; β = 0.325; p < 0.001) and by 3% (R2 = 0.71; β = 0.749; p < 0.001), respectively; when compared to weight alone.Compared with body weight, APMT presented a similar association with muscle mass, but showed a lower prediction of lean mass. In this way, the evaluation of body weight, instead of APMT, seems to have a better cost-benefit to predict both muscle mass and lean mass in kidney transplantation patients.