Objective: The aim of this study was to investigate the effects of parent's characteristics, physical and psychosocial symptoms, and child-related factors on caregiver burden of parents of children with cancer. Methods: This is a descriptive and cross-sectional study that included 172 parents of children with cancer. This study was performed between February and July 2019 in three major paediatric haematology and oncology units located in the centre of Turkey. Data were collected by using the descriptive information form, Pittsburgh Sleep Quality Index, Piper Fatigue Scale, Beck Depression Inventory, Trait Scale of the State–Trait Anxiety Inventory, Multidimensional Scale of Perceived Social Support and Zarit Caregiver Burden Scale. For data analysis, average and percentage calculations and multiple linear regression analyses were used. Results: It was found that most of parents had poor sleep quality, moderate depression, fatigue, anxiety, high social support and moderate to severe caregiver burden. It was found that low education level, poor sleep quality, depression, trait anxiety, social support among the factors related to the parents, and the type of treatment and duration of the treatment from the factors related to the child had an effect on the caregiver burden. It was determined that the effective predictive factors explained 73.5% of the parents' caregiver burden. Conclusion: Caregiver burden is influenced by the parent- and child-related factors. Paediatric oncology nurses should plan interventions that support parents to cope with the caregiver burden during their children's cancer experience.