Sarcopenia has been evaluated as a separate condition in cancer patients and as an important indicator of adverse outcomes. Muscle mass and phase angle are usually quantified by bioelectrical impedance analysis, due to its lower cost, and availability. The aim of this study was to assess the impact of sarcopenia, phase angle, and other characteristics on overall survival (OS) in palliative cancer patients at the National Cancer Institute of Mexico. We enrolled 628 patients (female, 59%). The most frequent disease was gastric cancer (39.5%). Kaplan-Meier analysis showed a significant survival disadvantage for patients with sarcopenia compared to patients without sarcopenia (p = 0.02). Sarcopenia univariably predicted OS [HR 1.4 (95% CI, 1.1-1.8), p = 0.001], but was not significant in multivariable Cox-regression analysis (p = 0.08). Significant predictors for sarcopenia in multivariable Cox-regression analysis were sex, age, body mass index, phase angle, clinical symptoms, and Karnofsky. Our results corroborate the reliability of sarcopenia and phase angle in Mexican population, showing that the measurement of these parameters might also be useful in early-stage cancer patients as prognostic markers.