Adherence to healthy diet principles and to cardiopreventive medication, both key behaviors in cardiovascular disease (CVD) prevention, is known to differ between women and men. Whether these adherence behaviors are differentially related among women and men has never been thoroughly assessed. The objective was to assess gender differences in the association between adherence to healthy diet principles and to cardiopreventive medication in adults free of CVD. This cross-sectional study included 268 women and 204 men from the CARTaGENE cohort (Québec, Canada) who were using antihypertensive and/or cholesterol-lowering medication. Adherence to healthy diet principles was assessed using the Alternate Healthy Eating Index (AHEI, %), calculated from a validated food frequency questionnaire (FFQ) assessing diet in the 12-month preceding its completion. Medication adherence was assessed using the daily pharmacotherapy possession rate (DPPR, %), calculated from prescription claim data over the same 12-month period. In multivariable-adjusted analyses, an inverse association between AHEI and DPPR was observed among men (βAHEI for 10% increment in DPPR=-0.65%; 95% CI: -1.28%, -0.03%; P=0.04), while it tended to be positive among women (β=0.44%; 95% CI: -0.11%, 1.00%; P=0.12; Pgender*DPPR=0.01). The negative association between AHEI and DPPR was stronger among men who never smoked or used cholesterol-lowering medication only. Among women, the positive association was stronger and statistically significant among those with obesity or using ≥3 medications simultaneously. Association between adherence to healthy diet principles and to cardiopreventive medication differs between women and men, with men potentially facing greater challenges in achieving optimal complementarity between these two behaviors.