Glucose-6-phosphate dehydrogenase (G6PD) enzyme catalyses the first step in pentose phosphate pathway (conversion of glucose-6-phosphat to 6-phospho gluconat) which provides cells with pentoses and reduction power in the form of NADPH. In the present study we have analyzed the G6PD gene mutations in 76 patients with a history of favism in Khorasan province in Iran. DNA samples were analyzed for the presence of certain known G6PD mutations by the appropriate (PCR/RFLP analysis). The results showed that similar to Gilan, Golestan and Mazandaran provinces, Mediterranean mutation is the most common G6PD variant in this area (66%). 12% of samples had Chatham mutation and none of the samples had Cosenza mutation. In comparison with the three provinces of Caspian sea shore, more samples did not have three investigated variants (22%) which required further sequencing to search for other mutations.