In order to measure the amount and type of aflatoxin produced in various cultivars of pistachio from Khorasan e Razavi Province, 4 cultivars of popular pistachio of Khorasan-e-Razavi were selected and collected. For this research, an isolate of aflatoxigenic Aspergillus flavus separated from the pistachio was used. Initially, 60 grams of pistachio kernels in 3 consecutive 20-gram sampling were selected and placed on Petri-dishes separately. 1 ml of the spore suspension of aflatoxigenic Aspergillus flavus added to each Petri-dish (spore suspension adjusted to contain of 2 × 10⁶ spore/ml). The plates placed over water in plastic boxes and then placed inside an incubator at 26°C. After 5 and 8 days of inoculation, growth rate and colonization of A. flavus on pistachio kernels measured in different cultivars. For the purpose of extraction of aflatoxin from pistachios; initially, contaminated pistachio nuts are dried inside the oven with a temperature of 60 ° C for 48 hours to prevent the fungi from growing and further production of aflatoxin. Then, the amount and type of aflatoxin in pistachios were analyzed with HPLC method. The results of the study demonstrated that among the examined cultivars, this isolate is able to produce both aflatoxin B₁and B₂. It is noteworthy that the isolate is not able to produce aflatoxins G₁ and G₂.The highest amount of aflatoxins B₁ and B₂ produced was for Daneshmandi cultivar and the lowest figure was for Garmeh.