Background This study aimed to evaluate the association of body composition with toxicity to first-line chemotherapy and three-year survival in women with ovarian adenocarcinoma. Methods We enrolled, in a retrospective cohort, 239 women treated with carboplatin and paclitaxel between 2008 and 2017. Pretreatment computed tomography scans were used to quantify skeletal muscle index (SMI), skeletal muscle radiodensity (SMD), and subcutaneous adipose tissue index (SATI). Chemotherapy doses, related toxicities, potential drug-drug interactions (DDI), and clinical variables were collected from medical records. Outcomes were the number of adverse events ≥ grade 3 toxicity, toxicity-induced modification of treatment (TIMT), and three-year survival. Results Average age was 56.3 years and 35.1% had myopenia. Almost 33% had TIMT and 51.3% presented any grade 3 toxicity. Potential severe DDI occurred in 48.1% of the patients and 65.1% died three years after the first treatment. The SMD and SATI below the median were independent predictors for the number of adverse events ≥ grade 3 and TIMT. Also, SMD was the only body composition parameter able to predict reduced three-year survival. The SMI was not associated with any of the outcomes. Conclusion Fewer amounts of SATI and low SMD were associated with the occurrence of toxicity to chemotherapy, and the low SMD increased the risk of death in the three years after oncologic treatment.