BACKGROUND AND OBJECTIVES: Pain for cancer patients might represent a worsening prognosis, decreased autonomy, well-being and quality of life, affecting all spheres of life of cancer patients and their repercussions on caregivers. Therefore, this study aimed to evaluate the impact of chronic pain on the quality of life and functional capacity of cancer patients and their caregivers. METHODS: Eleven caregivers and 15 cancer patients from a Pain Clinic were evaluated. To assess the functional capacity of the patients, we used the physical and instrumental activities of daily living scale and, for quality of life, we used the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30), which indicated impairment in social and emotional functions and prevalence of symptoms fatigue and insomnia. RESULTS: The average of the instrumental activities of daily living scores indicated a semi-dependence of the patients. There was a female predominance in patients (60%) and caregivers (72.2%). The average pain by the visual analog scale was 6.8. The Zarit Caregiver Overload Scale indicated that 36.3% of caregivers had moderate to severe overload and a positive correlation between functional capacity and overload (p=0.003). The impact of chronic pain on the quality of life and on the functional capacity of cancer patients and their caregivers O impacto da dor crônica na qualidade de vida e na capacidade funcional de pacientes oncológicos e de seus cuidadores