Aim To assess the quality of life in patients with malignant disease, to determine whether there are differences among patients regarding location of the malignant disease, age, gender, education level, marital or financial situation and place of treatment Study design Cross-sectional study conducted at the Radiotherapy and Oncology Department, Clinical Hospital Centre Osijek Research subjects and methods The research included 105 patients with malignant disease who receive stationary and daily treatment at the Radiotherapy and Oncology Department. A questionnaire was used as research instrument that contained demographic data including a scale measuring the quality of life in patients with a malignant disease, the Functional Assessment of Cancer Therapy-General (FACT-G). Results The average score of the scale is 89. With increase in age the level of satisfaction with social/family relations is significantly lower (p=0,027) in singles (p=0,018), and participants whose total income is less than 3 000 HRK (p=0,031). Regarding family and social relations there is a significantly higher level of satisfaction among patients who receive hospital day care (p=0,001), and among subjects with college/university education (p=0,007). Patients with malignant disease of the head and neck have significantly lower levels of satisfaction in all subscales and regarding overall health (p=0,005). Conclusion The quality of life of patients with malignant disease is satisfactory. Depending on the location of the malignant disease there is a significant difference among participants' quality of life in all health-related areas. The research participants aged between 51-60 years and those with lower income have the poorest quality of life. The overall satisfaction level is significantly higher amongst participants with college/university education. On the subscale of social/family relations the participants who receive daily hospital care express greater satisfaction with the quality of life.