to determine the quality of sleep, to locate the reasons for sleep disturbances and to define strategies overcoming sleep disturbances of cancer patients.175 cancer patients were included in this study. Data were collected using the Pittsburgh Sleep Quality Index (PSQI); a demographic data form and two open-ended questions on the reasons and coping strategies for sleep disturbances were filled in.the mean sleep quality score was 9.46 ± 4.669. The reasons given by patients for sleep disturbances were mostly cancer diagnosis (61.71%), adverse effects of therapy (58.85%), and financial problems (36.00%). Most patients (83.82%) used no pharmacologic strategies like lifestyle practices (64.25%), behavioral practices (21.25%), and biologic treatments (4.34%). Total PSQI scores of female patients were significantly higher compared to male patients, indicating poor sleep quality (Z=3.189; p=0.001). There was no statistically significant difference between age, education, illness duration, types of cancer and total PSQI scores (p>0.05).This research implied that cancer patients had poor sleep quality. Healthcare professionals should assess the sleep quality of cancer patients and solve this problem in a holistic perspective in order to provide a supportive environment during the caregiving process.