Aim: The overall aim of this thesis was to explore clinicians’ perceptions and self-efficacy regarding the use of the ‘Serious illness conversation’ structured workflow, and to explore their self-efficacy in caring for patients with palliative care needs. Methods: This thesis is comprised of four studies: two qualitative studies, one methodological study, and one quantitative study. In studies I and II, observations of clinic meetings and training sessions were undertaken with clinicians. Interviews were performed and a thematic analysis was conducted. In study III, the Self-Efficacy in Palliative Care scale (SEPC) was translated, adapted, and validated. In study IV, the SEPC-SE was completed by nurses and physicians. Factor analysis and Cronbach's alpha were calculated, and the Mann-Whitney U test was used to compare self-efficacy. Multiple linear regression was used to explore associated factors. Results: In study I, clinicians expressed that working with serious illness conversations was vital, but the conversations were also considered in terms of risks. The conversation training sessions created feelings of exposure but were perceived to be rewarding due to an increase in self-awareness. Obstacles in practice were identified as barriers to change. Study II showed that positive experiences and the group’s level of support, consensus, and behaviour was important for self-efficacy. Some clinicians were affected by perceived high demands, failures, anxiety, stress, when working with serious illness conversations. Study III showed that the SEPC-SE needed improvements in understandability and clarity. In study IV, the SEPC-SE reported high reliability. Physicians reported higher self-efficacy than nurses. Education at work and experience in advanced homecare had the strongest associations with self-efficacy. Conclusions: Implementing serious illness conversations can increase clinicians’ awareness about the importance of engaging in serious illness conversations and thus contribute to increased motivation through behavioural and attitudinal changes. However, building a support system for clinicians within the organisation seems essential for improving self-efficacy. The SEPC-SE was found to be valid and reliable. Clinicians’ estimation of their perceived self-efficacy indicates that healthcare organisations should prioritise work-related education and experience to improve self-efficacy in providing palliative care.