Background Family caregivers in cancer and palliative care often face heavy responsibilities and feel insufficiently prepared for the situation as caregivers. This study evaluates short‐term and long‐term effects of a psycho‐educational group intervention aiming to increase preparedness for family caregiving in specialized palliative home care. Methods The study design was a randomized control trial where family caregivers were allocated either to an intervention or control group. The intervention was delivered as a program including three sessions by health professionals (physician, nurse, and social worker/priest). Family caregivers from 10 specialized palliative home care settings were included. Questionnaires with validated instruments at baseline, upon completion, and 2 months following the intervention were used to measure effects of the intervention. The primary outcome was preparedness for caregiving in family caregivers. Results In total, 21 intervention programs were delivered, and 119 family caregivers completed all three measurements. The intervention group had significantly increased their preparedness for caregiving in both the short‐term and long‐term follow‐up compared with the control group. The intervention group also reported significantly increased competence for caregiving in short‐term but not long. No effects of the intervention were found on rewards for caregiving, caregiver burden, health, anxiety, or depression. Conclusions The psycho‐educational intervention has the potential to be used by health professionals to improve preparedness for caregiving among family caregivers in palliative care both in short and long terms. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.