Student-selected components (SSCs) encourage the following within the undergraduate medical curriculum: greater exploration of core curriculum topics; exploration of non-core subjects/experiences; research and self-directed learning; and personal and professional development opportunities. This study examined the motivational factors which influence SSC choice to assess (a) SSC selection patterns across each year of the curriculum (direct and graduate entry) and (b) motivation underlying SSC selection across the curriculum. During SSC registration at University College Cork, all medical undergraduates (years 1-3, graduate-entry medicine) were required to select an SSC and provide a written justification for their selection. Five primary motivational factors were identified: correction of perceived deficits; genuine interest in subject and wish to study in more depth; career strategy; exam strategy; and taking a chance. A complex pattern of relationships emerged in relation to matching of motivational factors with SSC categories, e.g. selection of research skills SSCs was strongly associated with the 'career strategy' motivation. Significant differences were observed across curriculum years, as well as between direct-entry versus graduate-entry undergraduates, with respect to SSC selections and underlying motivation. This study provides insight into changing patterns of SSC selection in medicine, as well as accompanying motivational factors, across the undergraduate years.