Purpose This study aims to determine the financial toxicity (FT) level in cancer patients, identify the risk factors associated with this level, and reveal the effect of this level on patient outcomes (health-related quality of life (HRQoL) and treatment non-adherence). Methods The data of 316 cancer patients, who were receiving inpatient treatment in an oncology hospital affiliated to a public university in Ankara, Turkey, were >= 18 years old, and were receiving chemotherapy for at least 3 months, were evaluated. The data were collected through a face-to-face interview. FT was measured with the COmprehensive Score for financial Toxicity (COST) Measure (v2), HRQoL was measured with the Functional Assessment of Cancer Therapy-General (FACT-G) Scale (v4), and treatment adherence was measured using a questionnaire created by conducting a literature review. Results Patients were found to experience FT above the moderate level (mean +/- SD, 21.85 +/- 12.02; median value, 24.0). Younger age, being married, low education level, low monthly household income, and receiving social/economic support for treatment were revealed to be the determinants of high FT. Moreover, as the FT score decreased (as the FT level felt increased), the HRQoL was observed to decrease, and treatment non-adherence increased. Conclusion The results indicate that FT problem is also valid for cancer patients in Turkey despite the system of general health insurance. The FT was found to result from socio-economic characteristics rather than the disease and treatment-related characteristics. The significant associations revealed between FT and patient outcomes emphasize the importance of reducing the FT in cancer patients.