This longitudinal study aimed at investigating Polish medical students' career choice motivation, factors influencing specialty choices, professional plans and expectations. The same cohort of students responded to the same questionnaire, at the end of Year 1 and Year 6. The Chi-square, Mann-Whitney U tests and logistic regression were used in analyses. The results showed that altruistic and scientific reasons were the main motives for choosing a medical career. The motives remained stable over time. The effect of gender on altruistic motivation was stronger at the end of the study, with females' rating higher. The most favored career paths were associated with non-primary care specializations and work in a hospital. Results of the multivariate logistic regression showed that primary care specializations were more attractive to females, final year students, those from small agglomerations, and those less concerned about high earnings. Preferences regarding sector of work were formed at later stages of training. A preference shift was observed, between Year 1 and Year 6, towards favoring work in the public sector. Predictors of the desire to work in the public sector were: being a male and the final year student, paying less attention to high earnings, wanting certainty of finding work, having a stronger need for interesting and socially important work. A significant decline in the level of interest in seeking employment abroad was observed with the progress of studies. Our findings are likely to provide useful information for educators, policy planners and policy makers.