Abstract: Age-related patterns of infection with human cytomegalovirus (HCMV) infection were studied in Cairo and South London. Testing for HCMV IgG antibodies showed that HCMV infection was acquired earlier in life in Cairo than in London, 95.6% of the general population in Cairo was seropositive by the age of 5 years compared with 33% in London. HCMV IgM antibodies were detected only in a small proportion of elderly individuals in both cities. Testing of urine specimens by virus culture showed that congenital infection with HCMV was more common in Cairo (1.3%), compared with 0. 6% in London. Urine samples from 8.6% of Egyptian children aged 2 weeks to 5 years were positive for HCMV by culture, compared with 3.6% aged 5-10 years and 5.6% aged 10-15 years. In children from London, HCMV was isolated from the urines of 11% aged 2 weeks to 5 years, 5.2% of those aged 5-10 years but from none aged 10-15 years.