Drug addiction is characterized by long-lasting risk of relapse even after long abstinence periods. Historically, addiction research mainly focused on males, generalizing the findings to females. However, clinical and preclinical studies revealed sex differences in cocaine relapse. Indeed, our previous study revealed a higher cue-induced cocaine seeking in female than male rats, an effect dependent on the hormonal cycle. Females were more vulnerable to cue-induced cocaine seeking during the estrus phase characterized by low progesterone levels, compared to females in non-estrus phase with high progesterone levels. Here, we studied whether endogenous and exogenous progesterone would decrease cue-induced cocaine seeking in rats.Female rats were trained to self-administer cocaine intermittently for 12 days and then underwent a cue-induced cocaine seeking test 29 days after forced abstinence. In the first experiment, blood sampling was performed after the relapse test and progesterone level was measured by ELISA. In the second experiment, the rats received an acute systemic progesterone injection before the relapse test.We observed that progesterone levels were negatively correlated with the number of active lever presses during relapse. Moreover, in estrus females, progesterone decreased cue-induced cocaine seeking compared to the vehicle group and decreased the number of c-fos+ neurons in the insular cortex. In non-estrus females, progesterone had no effect on cue-induced cocaine relapse and c-fos expression in the insular cortex.Our results demonstrate endogenous progesterone protective effect against cocaine seeking and suggest that exogenous progesterone treatment could prevent cocaine relapse in vulnerable estrus females via insular cortex activity modulation.