This study aimed to characterize Pseudomonas aeruginosa isolates in 2 intensive care units in Egypt and Saudi Arabia. P. aeruginosa isolates from patients' and staff hands and environmental samples were typed using antibiotyping and ERIC-PCR. In Egypt, isolates from suction apparatus tubing and drainage containers (A7) and AV tubing (A8) were linked to those from patients who had these antibiotypes. In Saudi Arabia, isolates from suction apparatus tubing (A6) and AV tubing (A7) were linked to patients with the same antibiotypes. In Egypt, patients' isolates had ERIC VII, VIII and IX patterns linked to suction apparatus tubing, AV machine tubes and drainage containers. In Saudi Arabia, patients' isolates had ERIC VIII and XI patterns linked to suction apparatus tubing and AV machines. In Egypt and Saudi Arabia, ERIC typing gave higher discriminatory indices (0.801 and 0.785 respectively) than the antibiotyping (0.7123 and 0.728 respectively). ERIC was superior to antibiotyping and should be used in tracing sources of infection.