Abstract: In the executed research on aquaculture diet in West Azerbaijan Province coldwater fish propagation and culture farms, which was accomplished by the kind cooperation and coordination of West Azerbaijan Province aquaculture department, samples of feed were evaluated during 2 phases, one phase between spring and summer and another phase between fall and winter, based on aflatoxin amount by HPLC technique. The feed samples used in this research were from different factories and of various kinds (SFT-FFT-GFT-BFT) and sizes. After the fulfilling of high performance liquid chromatography (HPLC) and evaluation of the test results in accordance with laboratory standards (the concentration was between 2-4 ppb). Result of samples of the second stage, fall and winter were negative, but of the samples of the first stage, spring and summer there were 5 positive samples. The total concentration of toxin (B1, B2, G1, G2) was between 1.21 to 6.62 ppb. The sample has been concentration of 6.62 ppb highly exceeded the allowed level. During these examinations, it was revealed that, the farms which had executed the hygienic principals of stocking, showed lower levels of toxin in the diet and vice versa. The toxin levels detected between spring and summer are higher than those of fall and winter due to the high heat and humidity of the warehouse.