Background: Although the overall gender gap in medicine is narrowing, significant gender disparities remain in the cardiothoracic surgery (CTS) field; women represent only 7% of practicing surgeons and 20% of residents. The purpose of this study was to identify gender differences in CTS exposure and interest among fourth year medical students applying to general surgery residency. Methods: An anonymous survey was emailed to general surgery residency applicants at a major academic program for the 2019 and 2020 application cycles. Data were stratified by gender and analyzed using the χ2 and t tests. Results: Of the 303 responders to the survey, 44% were women. A total of 58% of women were unlikely to be interested in or were definitely not interested in pursuing a career in CTS compared with 35% of men (P <.05). Men were 2.5 times more likely than women to be interested in CTS (odds ratio, 2.5; 95% confidence interval, 1.5 to 4.1). More men had rotated through CTS (55% vs 44%; P =.04) and shadowed a cardiothoracic surgeon (41% vs 29%; P =.03). More than 30% of women interested in CTS reported mentorship as the most important factor in their decision. Mentorship and CTS rotations were both independently associated with CTS interest after adjusting for gender. Conclusions: Interest in CTS is disappointingly low among women and represents a troublesome disparity that must be addressed. Early exposure to CTS and more mentorship from cardiothoracic surgeons are critical to reverse the current trend. Further studies are necessary to determine factors limiting female exposure to CTS rotations and dissuading female applicants from pursuing careers in CTS.