Genetically modified crops are produced using modern biotechnology to create or increase desirable traits such as increased efficiency or resistance to unfavorable factors. In recent years, Almost 200 million hectares of world crop acreage planted with GM crops including maize, so it is possible that GM maize has been imported to Iran especially as animal feed. Therefore, 25 samples of imported maize used for animal feed were tested to detect probable GM maize. The DNA of samples was extracted by CTAB method and its quality and quantity were evaluated by electrophoresis and spectroscopic methods and their amplifiability confirmed by PCR using the internal maize genomic gene of Zein based on INSO 10763. Detection of GM varieties was performed by the polymerase chain reaction (PCR) method based on INSO 9617 using primers CaMV 35S, NOS terminator, npt II marker gene generally existed in GMOs. According to PCR results with primers specific for sequences common in GM organisms, in 3 samples out of 25 samples a 195 bp band related to CaMV 35S promoter and in 3 feed samples out of 25 samples a 118 bp band related to NOS terminator were observed, 2 of them showed both sequences. The band related to nptII marker gene was observed in none of samples. These results can lead to the probability of existing of GM ingredients in samples. In order to identify that the observed electrophoretic bands are belonged to the GM organisms, some confirmation tests are needed.