Two hundred and twenty-nine infants born consecutively at the maternity ward of the Middelheim Hospital in Antwerp, over a period of 5 months, and an additional 55 randomly selected infants born at the same hospital were clinically and microbiologically investigated before leaving the maternity ward. All infants born at this maternity ward received argyrol eye drops immediately after birth. Twenty-six (11%) of the infants consecutively investigated had neonatal conjunctivitis diagnosed before leaving the maternity ward, where they stayed from 7-10 days. Another 29 infants were reported to have developed sticky eyes and/or red eyes after leaving the maternity hospital and before 1 month of age. The instantaneous risk of developing, a conjunctivitis was equal for each day of the first month of life. Chlamydia trachomatis was isolated from the eyes of 11 of the 229 (4.8%) consecutively born infants but only one had conjunctivitis symptoms before leaving the maternity ward. Overall one or more bacterial species could be isolated from the eyes of 143 (48%) of the infants, but only viridans streptococci and Staphylococcus aureus were cultured significantly more often from the eyes of cases with conjunctivitis than from the eyes of the infants without conjunctivitis (P less than 0.001).