The present study examined the role of μ- and δ-opioid receptors in alcohol drinking using antagonists selective for these receptor types. Food- and water-sated male and female AA (Alko, alcohol) rats consistently drank 10% alcohol during daily 30-min access periods in their home cages in the middle of the 12-h light phase. On 3 consecutive days, the animals received the μ-opioid receptor antagonist D-Phe-Cys-Tyr-D-Yrp-Orn-Thr-Pen-Thr-NH2 (CTOP, 1 μg ICv), the δ-receptor antagonist N,N-diallyl-Tyr-Aib-Aib-Phe-Leu-OH (ICI 174,864, 3 μg ICV), or saline 15 min before the alcohol access period. Relative to saline, the μ-antagonist CTOP decreased alcohol drinking both by males and females progressively over the 3 treatment days, with a continued suppression on the first days after the termination of the administration. Treatment with the δ-antagonist ICI 174,864 had no effect on alcohol drinking in males, and produced transient hind limb dysfunction and barrel rolling over half of the females. These results suggest that selective blockage of μ-opioid receptors is sufficient to suppress alcohol drinking in AA rats.