Asymmetry analysis have been carried out for five bilateral characters of Upeneus doriae (Günther, 1869) (Osteichthyes: Mullidae) collected from a coastal area near Muscat City in the Middle region of the Sea of Oman. The results showed that the level of asymmetry of the preorbital length is higher than those of the other characters studied. The number of pelvic fin rays showed the lowest asymmetry value. The possible cause of the asymmetry in this species has been discussed in relation to different pollutants and their presence in the area. A trend of increase in the asymmetry values with the fish length was noticed in the pre- and post-orbital lengths and head length.
