Newcastle disease (ND) is a highly contagious disease that affects many species of birds and causes significant economic losses to the poultry industry worldwide and the pathogenicity of Newcastle disease virus (NDV) strains varies with different virulence. Samples were collected from chicken commercial farms in Iran during 2014–2015. ND virus were characterized (NDV) by partial sequences of fusion genome and compared with other NDV sequences. All viruses showed the amino acid sequence 112 RRQKRF117 at the C-terminus of the F2 protein and phenylalanine at the N-terminus of the F1 protein, residue 117. These amino acid sequences were identical to a known virulent motif. Based on the phylogenetic analysis the Iranian ND isolates are closely related to the genotype VIId of class II NDV strains. The result show that the genotype VIId is dominant and circulating among chicken farms and cause clinical disease.