The purpose of this study was to evaluate the effect of a combined treatment with carprofen and enalapril on ductus construction in the medical treatment of Golden retriever dogs with PDA which are unable to undergo surgical treatment and have delayed diagnosis. PDA was diagnosed by using Doppler, echocardiography, electrocardiography, X-ray, and blood analysis in 5 golden retrievers. Carprofen (2 mg/kg) and enalapril (0.5 mg/kg) were administered daily for 12 months and the dogs were controlled at 3 monthly intervals. Ductal construction was detected as 11% (p = ns) at the 3rd month, 24% (p < 0.05) at the 6th month, and 31% (p < 0.01) at the 9th month and 38% (p < 0.001) at the 1st year. An increase in the diameter of the main pulmonary artery was revealed after the 9th month (p < 0.05). No significant alteration was determined in the diameter of aorta, fractional shortening (FS %) and ejection fractioning (EF %) during the treatment. The results of the study indicated that the effect of a combined treatment of carprofen and enalapril is revealed after a long time period. Although a statistically significant decrease occurred in the diameter of the ductus, no complete closure in the ductus occurred. It was also detected that the severity of clinical signs in the dogs with PDA type-2, which had rendered them unacceptable for operation, was decreased by this medication.