Cancer research relies on key values such as creativity, collaboration, research integrity and resource sharing. A positive research environment which fosters these key values is becoming a decisive factor for some funders and research institutions. To create a supportive research culture in laboratories, the training and mentoring of young scientists is important. However, the fast-paced and fierce competition for funding and jobs can present a challenge to the younger generation of scientists who depend on the guidance and mentorship of scientific leaders. The annual Nature Awards for Mentoring in Science have been created to bring attention to one of the most essential but least recognized skills in scientific leadership. Thus far, 35 scientists from across the world, who are working in a range of disciplines, have been recognized by this award for their outstanding scientific mentorship. In this Viewpoint, we have asked three recipients of this award who work in fields associated with cancer research about their views on good mentoring, and how a revised approach to mentorship can help to achieve a positive research culture and contribute to scientific discovery.