Female rats’ sexual behavior is highly motivated. As the mesolimbic dopaminergic system is implicated in decision-making related to the energy cost associated with different rewards, we hypothesize that manipulating this system reduces sexual interaction in females if another reward is also available. We are validating a model of time investment preference between two rewarding activities: one more active, sexual interaction, and another more sedentary, eating palatable food (FrootLoops), in rats tested in proestrus phases of the estrous cycle. Following three training sessions —exposure to separate stimuli: male (with vaginal mask) and food— within a three-chamber model, females interacted simultaneously with both stimuli. In successive proestrus, they were tested with both stimuli after counterbalanced administration of the dopaminergic antagonist haloperidol: 0.1 or 0.2 mg/kg. When both stimuli compete, females perform both activities but spend more time on sexual interaction. Haloperidol reduced the display of proceptive behaviors, but increased the time females spent with the male, leading to a decrease in food intake. These results suggest that reduced dopaminergic transmission directs the allocation of limited energy resources toward preferred rewarding activity, sexual interaction. To strengthen the model, we will pharmacologically challenge this choice in a situation where the physical effort required to access the male is greater than that required to access food.