Purpose: Pain is a multifactorial and subjective experience. Psychological and social factors can modulate it. This study analyzed whether and how prolonged cancer pain is related to the social-relational environment's characteristics. Specifically, we investigated whether the caregiver's emotional support, his/her compassion ability or, on the contrary, his/her personal distress, associates with the patient's pain level. Methods: The sample consisted of 38 cancer patients suffering from pain and 38 family caregivers.