Background and Objectives: The impact of sarcopenia and myosteatosis on renal transplantation (RT) outcomes has yet to be explained, certainly due to differences in assessment methods. The role of visceral adiposity is also not clearly defined. This retrospective study aimed to evaluate pretransplant body composition—including sarcopenia, myosteatosis, and visceral adiposity ratio (VSR)—using computed tomography (CT) and analyze their relationship with short- and long-term graft outcomes. Materials and Methods: A total of 94 patients who underwent RT between 2019 and 2023 and had pretransplant non-contrast abdominal CT scans were included. Skeletal muscle area (SMA) was assessed at the L3 vertebral level, including multiple muscle groups. Sarcopenia was defined by a low skeletal muscle index (SMI), while myosteatosis was defined by high intramuscular adipose tissue content (IMAC). Visceral adiposity was evaluated by the visceral-to-subcutaneous adipose tissue ratio (VSR). These parameters were compared with post-transplant outcomes. Results: The mean age was 42.69 ± 12.47 years, with 54.3% male patients. High IMAC was significantly associated with early graft failure (p = 0.026), delayed graft function (p = 0.005), death-censored graft failure (p = 0.036), and overall graft failure (p = 0.047). One-year mortality was also higher in the high IMAC group (14.8% vs. 0.0%, p = 0.012). SMI and VSR were not significantly associated with outcomes. Myosteatosis emerged as a significant risk factor in univariate analysis but was not independently predictive in multivariate analysis. Among the established risk factors identified in the study, recipient age was found to be a significant predictor for overall graft failure, donation type (cadaveric vs. living) for death-censored graft failure, and cold ischemia time for delayed graft function (OR: 1.068, 95% CI: 1.001–1.141, p = 0.049; OR: 147.7, 95% CI: 2.1—10,427.0, p = 0.021; OR: 1.003, 95% CI: 1.001–1.006, p = 0.023). Conclusions: Myosteatosis correlates with worse graft outcomes and higher mortality, but its independent prognostic value requires further investigation.