Purpose: The Carer Support Needs Assessment Tool (CSNAT) was developed for use among family caregivers in palliative care for assessment of their support needs. The purpose of this study was to translate and evaluate the validity and reliability of the CSNAT in a sample of Swedish family caregivers and nurses in a palliative care context. Methods: Data for this validation study was collected during 2016 in the context of palliative home care in two larger Swedish cities. The study was conducted in three stages to reach conceptual, semantic, operational and measurement equivalence between the original UK version and the Swedish version. Stage I consisted of translation to Swedish. In Stage II, cognitive interviews were performed with 8 family caregivers and 10 nurses. Data were analyzed based on relevance, clarity and sensitivity. In Stage III, the CSNAT and related self-rating measures (caregiver burden, preparedness for caregiving and quality of life) were completed by 118 family caregivers. Data quality, construct validity and test-retest reliability were evaluated. Results: The CSNAT items were considered relevant and useful to identify areas of support needs. The Swedish CSNAT showed sound psychometric properties with satisfactory data quality and few problems with missing data across items (1.8%-6.1%). All items except one correlated as expected (rho > 0.3) with caregiver burden, supporting construct validity. All items had satisfactory test-retest reliability (kappa w = 0.45-0.75). Conclusions: This study further adds to the validity of the CSNAT and shows in addition that it is reliable and stable for use among family caregivers in palliative care.