Professional values and behaviours are intrinsic to all medical practice, yet remain one of the most difficult subjects to integrate explicitly into a curriculum. Professionalism for the twenty-first century raises challenges not only to adapting the course to changing societal values but also for instilling skills of ongoing self-directed continuous development in trainees for future revalidation. This Guide is based on the contemporary available literature and focuses on instilling Professionalism positively into both undergraduate and postgraduate training deliberately avoiding the more negative aspects of Fitness to Practise. The literature on Professionalism is extensive. An evidence-based approach has been taken throughout. We have selected only some of the available publications to offer practical advice. Comprehensive reviews are available elsewhere (van Mook et al. 2009a-g). This Guide takes a structured stepwise approach and sequentially addresses: (i) agreeing an institutional definition, (ii) structuring the curriculum to integrate learning across all years, (iii) suggesting learning models, (iv) harnessing the impact of the formal, informal and hidden curricula and (v) assessing the learning. Finally, a few well-evaluated case studies for both teaching and assessment have been selected to illustrate our recommendations.