Abstract In a population of 1928 neonates in Northern Norway, ophthalmia neonatorum was diagnosed in 18.9%, including mild and self-limiting cases. Sixteen out of 269 (6.0%) cultured cases were positive for Chlamydia trachomatis. No gonococcal ophthalmia was seen. In neonates whose symptoms began in the maternity wards, the distribution of the isolated microorganisms (mainly Staphylococcus aureus) was different from those in whom symptoms began after discharge (mainly S. aureus, Staphylococcus species (coagulase-negative), Streptococcus viridans and C. trachomatis). Growth of C. trachomatis was significantly associated with the intensity of conjunctivitis (P<0.001). However, no sequelae could be demonstrated in the eyes at the age of 6 months. 60% of the neonates with chlamydial ophthalmia also suffered from rhinitis. 31.4% of the neonates received silver nitrate instillation, which had no significant influence on the frequency of chlamydial ophthalmia. General practitioners are often faced with chlamydial ophthalmia. In cases of ophthalmia neonatorum, a microbiological examination is recommended, as a guide to appropriate antibiotic treatment. The result of microbiological examination may also indicate other infections in mother and child. In areas with a readily available health service, including an adequate microbiological laboratory service, prophylaxis in the eyes does not seem to be necessary.