Ovarian cancer patients often face poor nutritional status, with body composition (BC) serving as a significant prognostic indicator. Skeletal muscle mass (SMM) and fat-free mass (FFM) are crucial predictors of both survival and hospitalization duration. Increasing protein intake has been linked to improvements in SMM and FFM. This study aimed to document the alterations in BC parameters among ovarian cancer patients undergoing chemotherapy and correlate these changes with their nutrient intake. Twelve female patients with stage III ovarian cancer who received first-line chemotherapy were categorized based on their body mass indices (BMI). BC parameters were assessed using an 8-point bioelectrical impedance analysis with a frequency of 50 Hz-60 Hz and measurement impedance range of 10 Ω-1000 Ω. Nutrient intake (energy, protein, fat, and carbohydrate) was assessed before (T0), during the 3rd (T3), and 6th cycle of chemotherapy (T6) through 24-hour food recall. Significant increases in body weight (BW)were observed in the underweight group (from 40.9 to 46.8 kg, p=0.001), concomitant with enhancements in all BC parameters. While changes were noted in SMM, they were not statistically significant (p=0.105).Among the underweight group, a protein intake above 1.2 g/kg BW led to an uptrend trend in SMM. Conversely, FFM in overweight/obese patients decreased significantly (from 37.6 to 36.4 kg, p=0.005) due to a a reduction in body water. Throughout chemotherapy, fat mass (FM), visceral fat (VAT), and phase angle (PhA) increased in all patient groups, reflecting heightened fat and carbohydrate intake. Among stage III ovarian cancer patients, BC undergoes dynamic changes dynamically during the course of chemotherapy, with more pronounced enhancements observed in FFM among underweight patients. Notably, improvements in PhA, SMM or FFM were particularly evident among underweight patients with a protein intake above 1.2 g/kg BW.