We investigated the effect on bacterial flora of conjunctival irrigation as part of the chemical preparation of the eye before surgery. Forty consecutive patients underwent conjunctival irrigation with a saline solution in one randomly selected eye. Aerobic and anaerobic bacterial conjunctival cultures were taken in masked fashion before and after the preparation. In nonirrigated eyes, the colony counts before and after the preparation were virtually identical; the species count increased 23%. In irrigated eyes, the colony count increased 18% and the species count increased 46%. The increase in the species count was significant. Our findings suggest irrigation with a saline solution does not reduce the bacterial flora of the conjunctiva.