Our aim is to assess the quality-of-life (QoL) of cancer patients and the effect of sociodemographic characteristics, medical history, and disease Management, on QoL. The present study included 318 cancer patients. The most common diagnosis in this study were breast cancer (30.0%) and gastrointestinal cancer (27.7%). A form exploring sociodemographic variables and the EORTC QLQ-C30 questionnaire were used to collect patient data. Non-parametric tests were employed to evaluate the association of different factors with patient QoL. Sociodemographic characteristics such as age; gender; level of education; employment status; and medical history, including any family history of cancer, date of diagnosis, cancer awareness, stage of the disease, past/current treatments, use of painkillers, and psychiatric support, significantly affected the QoL of cancer patients. The mean QoL score was moderate (56.05%+/- 26.42). Physical functioning was the most affected subdomain (63.27 +/- 25.69), and cognitive functioning the least affected (78.35 +/- 23.47). Our results indicate a relationship between many clinical and sociodemographic factors and the QoL of cancer patients. Healthcare professionals should be aware of factors that affect QoL so that patient complaints and needs can be adequately addressed to improve patient QoL.