BackgroundLack of smoking cessation education in undergraduate medical training hinders healthcare professionals in providing adequate tobacco cessation counselling.We developed a comprehensive 4-h smoking cessation counselling course for medical students that is easy to incorporate in a medical school curriculum, and assessed its short-term outcome for knowledge, skills, and attitudes.MethodsEighty-eight medical students (53f, 35 m) were educated by a doctoral student in five identical 4-h courses. A 45-min theoretical introduction was followed by patient-physician role-playing by student pairs. Knowledge, skills, and attitude were assessed before and 4 weeks after the course by questionnaires, and by blinded analysis of pre- and post-course videos of a five-minute standardized patient situation.ResultsKnowledge: Before the course 10.6 (mean, SD: 2.7) questions out of 29 were answered correctly, and increased to 19.2 (3.6) after the course (p < 0.0005). Major features of the students’ counselling skills improved. Significant and highly relevant attitude changes reflected increased motivation to counselling smokers.ConclusionImplementing a four-hour smoking intervention workshop into a medical curriculum was highly effective in improving students’ knowledge, skills and attitudes towards smoking counselling, as well as providing them with additional clinical competencies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12971-016-0103-x) contains supplementary material, which is available to authorized users.