New national clinical guidelines are now available on advance care planning (ACP). Confidence in communication is important for implementation of the guidelines. This study aims to identify healthcare personnel's self-perceived confidence in communication about future medical care and patients' wishes at the end of life. Healthcare personnel in twelve geriatric units in South-Eastern Norway Regional Health Authority responded to an online questionnaire survey in autumn 2022. The four response alternatives for self-reported confidence - 'unconfident', 'fairly confident', 'very confident' and 'extremely confident'- are combined into two categories: 'limited confidence' ('unconfident' and 'fairly confident') and 'high confidence' ('very confident' and 'extremely confident'). We received responses from 289 of the 470 (61.5%) invited, with an average age of 37.8 ± 11.3 years, of whom 217 out of 289 (75%) had more than five years of professional experience. Of the doctors, 15 out of 67 (22%) reported limited confidence in communication about 'future deterioration of the patient's health condition', 20 out of 67 (30%) about 'life-sustaining treatment' and 13 out of 67 (19%) about 'preferences towards the end of life'. For other healthcare personnel, the corresponding responses were 119 out of 222 (54%), 140 out of 222 (63%) and 109 out of 222 (49%). Self-assessed confidence in communication about future deterioration, future medical care and the patient's own wishes at the end of life varies, and such confidence is limited among many health personnel in geriatric units. Measures appear to be needed to increase confidence in the communication and implementation of ACP in the Norwegian health service.