This study was carried out to determine the serotypes species of Aeromonas bacteria causing Carp Erythrodermatitis in Cyprinus carpio L. fishes in Hama Governorate, Syria and to identify their sensitivity to some common antibiotics and sulphonamides. Two hundred and fourteen samples of diseased fishes were collected from different areas of Governorate of Hama. Ulcers of the disease were classified into primary, secondary and advanced and the isolation of bacteria was performed for Aeromonas species and confirmed by polymerase chain reaction (PCR). The isolated bacterial species of Aeromonas were distinguished by biochemical tests. The results showed that Aeromonas salmonicida subsp. Achromogenes was found to be the main cause of Carp Erythrodermatitis as it was isolated from 89.2% of the primary ulcers. Aeromonas salmonicida subsp. Salmonicida and Aeromonas hydrophila were isolated only from 9.5% and 1.4% % of the primary ulcers respectively. Most bacterial species of Aeromonas isolated from Carp Erythrodermatitis were highly sensitive to Nitrofuran and Florphenicol antimicrobial. It can be concluded that Aeromonas salmonicida subsp. Achromogenes is the main cause of Carp Erythrodermatitis in Carp fishes and it is most susceptible to Nitrofuran and Florphenicol.