Background Medical students’ choice of their future specialty is influenced by several factors, including working conditions and type of patient relations. The aim of this study was to investigate the association between the choice of specialty and personality traits.

Methods This is a cross-sectional questionnaire-based study of 399 alumni from Karolinska Institutet Medical School who were assumed to undergo specialty training at the time of the survey in 2013. The Big Five Inventory was used to assess the personality traits extraversion, agreeableness, conscientiousness, neuroticism and openness to experience. Medical specialties were categorised as primary care, psychiatry, internal medicine and surgical and hospital service specialties. Adjustments were made for demographic factors and the method of selection for medical school admission.

Results The response rate was 72% (n=289, of which 262 were in training to become specialists). Among these, surgeons scored lower in agreeableness than physicians in primary care, internal medicine and hospital services. Psychiatrists and hospital service physicians showed lower conscientiousness compared with surgeons.

Conclusions We found distinctive differences in personality traits between medical specialties even after adjusting for other potential explanatory variables. Since there are differences between specialties, for example, surgeons and psychiatrists, this supports previous findings that personality may affect medical students’ specialty choice also in a Swedish setting.