ArtículoABSTRACT: A group of does (n = 10) received 0.5 mg NX at 12 hr. intervals two days before and two days after mating, a control group (n = 10) was sham treated with saline injections. After kindling, kints born, nursing time and kint growth was studied. NX treated does nursed their kints for 235 ± 11.3 secs vs controls 220 ±16.2 secs (P<0.05). Milk yield and Kint weight was significantly higher in naloxone treated does.Kints born from control and naloxone treated does was 10.1  1.1 and 12.13  0.77 (P<0.05). Kints born live from naloxone treated and control dams was 11.3  0.94 and 9.5  0.9 (P<0.05). NX treated does weaned 10.0  0.9 kints, controls 8.7  1.05 (P<0.05). It was concluded that endogenous opioids are important modulators of nursing behavior in rabbit does favoring the development of their young.