Background and aims Pain is a prevalent problem in many countries. Women are more often on sick-leave for pain than men. Such gender differences have been explained through biological factors, different demands for on the job market, and home conditions. Fewer studies have focused on how gender stereotypes may bias the medical assessment of pain patients. The aim of the present research was to investigate if a gender bias in medical students' evaluations of chronic pain patients can contribute to explaining the gender differences in sick-leave due to pain. Specifically, we investigated whether medical students' estimates of a patient's accuracy of their own work ability and amount of domestic work differed between female and male patients, and how such estimates influenced the medical students' judgments of the patient's work ability. Methods Medical students (n=137; 60 women; 74 men; three unspecified) read a vignette describing a patient with pain and filled out a questionnaire. The vignette was identical and gender neutral, except for the name of the patient signaling gender. A between-subjects experimental design was used in which participants were randomly assigned to an experimental condition. Participants then judged the patient's work ability, the accuracy of the patient's self-assessed work ability, and the amount of domestic work they believed was performed by the patient. All ratings were made on seven-point items. Results The results showed that there was no main effect of gender on perceived future work ability of the patient, F (1,131)=0.867, p=0.353. However, male patients were considered to be more accurate in their self-assessed work ability than female patients F (1,131)=5.925 p=0.016 (Mfemale=4.87, SDfemale=1.22, and Mmale=5.33, SDmale=1.02). Moreover, female patients were thought to perform more domestic work, F (1,131)=25.56, p<0.001 (Mfemale=4.14, SDfemale=1.41, and Mmale=3.07, SDmale=1.16). Finally, perceived amount of domestic work moderated the effects of perceived future work ability for female but not for male patients, B=0.42, p=0.005. Hence, there was a positive effect of amount of domestic work performed on work ability judgments for women, such that the more domestic work they were assumed to perform, the more they were perceived to be able to work. Conclusions Gender stereotypes influenced assessments of future work ability in pain patients, mainly because women were assumed to perform more domestic work which had a positive effect on perceived work ability. Because domestic work should have a negative effect on recovery, expectations from the physician that domestic work is expected by female patients may in fact have the opposite effect prolonging sick-leave. Moreover, the students trusted the male patients' ability to assess their own work capacity more than women's. Implications It is important that medical students receive education about gender biases and how they may influence medical assessment during their training. Such education may alleviate the influence of gender stereotypes.