Aspergillus flavus produces secondary metabolites called aflatoxin that has powerful teratogenic, mutagenic and hepato-carcinogenic effects. The aim of this study was to evaluate the A. flavus of pistachio and peanuts from Sanandaj, Iran. Pistachio and peanut nuts samples were obtained from dried fruit retail shops of Sanandaj, 2011. One hundred grams from each sample were sterilized in a 0.4% sodium hypochlorite solution for 2 min. Subsequently, the sample was rinsed once in distilled water and allowed to dry. Each sample was grounded into powder by vortex and then 1 g was poured into 100 ml of sterile distilled water and stirred. Next, 1 ml of the supernatant was inoculated into Petri dishes containing Sabouraud dextrose agar then incubated at 25°C for five days. The grown fungi were identified by standard mycological techniques based macroscopic and microscopic morphology. Of the 132 samples (peanut: n = 81; pistachio: n = 51), fungi were detected in almost 72% of the samples. The A. flavus was the most predominant isolate from peanut (19%) and pistachio (22%) samples. There was a significant relationship between A. flavus contaminations in the peanuts and pistachio with high humidity. Therefore, due to the isolation of high percentage of A. flavus as the main aflatoxins producer in nature, we recommended the need for good storage practices in order to prevent the occurrence of aflatoxins in peanuts and pistachio.