Background: Undergraduate medical training should ensure students have choice and autonomy in the learning process, including the student selected components (SSCs) which should comprise up to about a third of the curriculum. Students' choices of SSC will influence the knowledge, skills and attitudes they acquire. Aim: To investigate how motivations and personality in first year medical students influence their choice of SSCs. Method: A questionnaire regarding motivations for SSC choice and the NEO-FFI personality measure was administered to all first year students at a London medical school. Relationships with type of SSC were examined. Results: A total of 82% (268/329) students responded. Six motivational factors arose from a principle components analysis of the questionnaire: future achievements, prior information, internal motivation, personal recommendation, convenience and certainty. Students with different motivational factors chose different SSCs, and had different personality traits. Weak but significant correlations were found between personality traits and motivational factors, but not between personality and SSC choice, or sex and SSC choice. Conclusions: This offers insight into medical student choices of SSC and is the first step towards ensuring appropriate provision of modules that students wish to study to enable them to meet the demands of the medical profession.