In this study, we aimed to determine serum concentrations of carotenoids and fat-soluble vitamins (FSVs) in ovarian cancer (OC) patients categorized by clinical and nutritional status and to compare obtained results with healthy controls. We used single-step extraction methods throughout the study. Serum concentrations of the bioactive compounds were measured using HPLC. The evaluation of the nutritional status of patients was performed with scored PG-SGA questionnaire.The serum bioactive compound levels were significantly lower in early-stage OC patients (FIGO I/II) when compared to healthy controls for all-trans-retinoic acid, 25-hydroxycholecalciferol, all-trans-retinol, astaxanthin, zeaxanthin, lycopene and α-carotene, respectively. In patients with advanced-stage of OC (FIGO III/IV) the mean serum concentrations of carotenoids and FSVs were significantly lower than in healthy controls, excluding lutein and β + γ-tocopherol levels. Patients with OC and concomitant moderate or severe malnourishment showed significantly lower levels of 25-hydroxycholecalciferol and all-trans-retinol. It seems that our extraction and measurement methods for the bioactive compounds could be used in both, clinical and nutritional studies. The obtained results confirm that the PG-SGA assessment might be considered not only as a malnutrition assessment tool, but also for planning early nutritional intervention in patients with OC.