Abstract Ivermectin (IVM) is an antiparasitic drug that is widely used in domestic animals. In mammals, IVM act as a γ-aminobutyric acid (GABA) receptor agonist. This neurotransmitter plays an important role in the regulation of female sexual behavior. The present study investigated the effects of therapeutic (0.2mg/kg) and high (1.0mg/kg) IVM doses on female sexual behavior in physiological and pharmacological conditions. Female rats in estrus or treated with estradiol valerate to induce sexual behavior 24h before the experiments were employed. Ivermectin was administered 15min before the sexual observations. The number of lordosis events in 10 mounts was recorded to calculate the lordosis quotient. The intensity of lordosis (0 [no lordosis], 1 [low lordosis], 2 [normal lordosis], and 3 [exaggerated lordosis]) was scored. In estrus and hormonal treated female both IVM doses decreased the intensity of the lordosis reflex and the percentage of females that presented high levels of lordosis (exaggerated lordosis). However, the number of females that presented lordosis was unaltered. We conclude that in both hormonal conditions IVM 0.2mg/kg treatment reduced female sexual behavior and the execution of the lordosis reflex. The present results may be useful for avoiding the side effects of this drug in veterinary practice.