Abstract Background and Aims Sarcopenia is a risk factor for adverse outcomes in older adults and dialysis patients, but this has yet to be confirmed in kidney transplant recipients. This study aimed to investigate the association of sarcopenia with all-cause mortality in kidney transplant recipients. Method In this single-center prospective cohort study, kidney transplant recipients were evaluated at baseline muscle mass, muscle strength, and physical performance using a hand dynamometer, 10-m walk test, and bioelectrical impedance analysis, respectively. Sarcopenia was defined according to the Asia Working Group for Sarcopenia 2019 criteria. Propensity score matching was used to reduce bias between the sarcopenia and non-sarcopenia groups, adjusted for three potential confounding variables including age, sex, and body mass index. After a 5-year follow-up, patient survival was assessed by the Kaplan-Meier method and Cox proportional hazards model in the matched cohort. Results Out of 212 patients (median age, 54 years; median transplant vintage, 79 months) enrolled in this study, patients who had sarcopenia at baseline was 33 (16%). After 1:1 propensity score matching, a matched cohort with 62 patients was generated. In the matched cohort, the overall incidence density rates of mortality were 48.8 and 6.75 per 1000 person-years in the sarcopenia and non-sarcopenia groups, respectively. The survival curves estimated using the Kaplan-Meier method indicated that the sarcopenia group was significantly lower cumulative survival than the non-sarcopenia group (log-rank test, p = 0.025). Moreover, the sarcopenia group had a significantly higher mortality risk than the non-sarcopenia group (hazard ratio = 7.59, 95% confidence interval = 1.93–61.7). Conclusion Sarcopenia was a significant predictor of mortality in kidney transplant recipients.