Brucella spp. is a gram negative coco bacillus which has different hosts including human, cow, goat, sheep and horse. While infection with Brucella in endemic region still remains, rapid and simple detection of Brucella seems necessary to prevent and treatment of the disease. The aim of this study is Detection of Brucella spp. in dairy products using Nested and Hemi Nested PCR techniques and comparing the techniques’ sensitivity and specificity. In this study 57 raw cow milk samples, 34 pasteurized cow milk samples, 28 pasteurized cheese samples, 23 traditional cheese samples, 33 raw sheep milk samples, 33 raw goat milk samples, were collected from Tehran province. DNA was extracted by using DNP kit from samples. After optimization of PCR for the two techniques of Hemi Nested and Nested PCR sensitivity and specificity of the two techniques were evaluated. In Nested PCR, among 57 samples of raw cow milk, 19 cases were PCR positive. In 34 pasteurized milk samples 10 cases were PCR positive, from 28 pasteurized cheese samples only 8 cases, from 23 traditional cheese DNA samples 14 cases, from 33 samples of raw goat milk 21 cases and finally from 33 samples of raw sheep milk 19 cases were PCR positive. With respect to these results, Nested PCR technique investigated in this study has significant sensitivity and accuracy compared to Hemi Nested PCR technique; therefore, the molecular technique as a confirmatory method in detection of Brucella spp.