Sarcopenia in cancer patients often negatively impacts various outcomes. Carboplatin, a first-line chemotherapy for non-small cell lung cancer (NSCLC), is dosed based on body weight, which doesn't account for sarcopenia. This study evaluated the association between sarcopenia and carboplatin-related toxicity in NSCLC patients. Patients with locally advanced or metastatic NSCLC treated with carboplatin were included. Toxicity events during the first two cycles of treatment were recorded. Sarcopenia was assessed using pretreatment computed tomography scans analyzed with Slice-O-Matic V4.2 software, defining sarcopenia as a skeletal muscle index (SMI) of <52.4 cm