A total of 70 Aeromonas isolates isolated from 100 Oreochromis niloticus, 100 Mugil cephalus and 50 water samples from El Gamil region in Manzala Lake were investigated for antibiotic susceptibility test to 14 different antimicrobial agents using disc agar diffusion method. All strains showed (100%) sensitivity to norfloxacin and showed high sensitivity to cefotaxime (91.4%), gentamycin (90%), nalidixic acid (80%), amikacin (78.6%) and chloramphenicol (74.3%). On the other hand, all tested isolates were resistant to ampicillin, erythromycin and penicillin and they exhibited high resistance rate to vancomycin (94.3%) and doxycycline (91.4%). Multiple antimicrobial resistance (MAR) index values of the tested isolates were higher than 0.2. They were 0.38, 0.36, 0.36 and 0.37 for A. hydrophila, A. sobria, A. caviae and A. schubertii, respectively.