The Caldwell-Luc operation was performed on 38 patients with and without the counteropening at the inferior meatus in order to investigate whether the opening is necessary or not. The blood loss with the opening was 108 g more on average than that on the side without it. The operation time was 11 min longer in the group with a counteropening. The differences in these two items were statistically significant. The difference in cheek swelling with both methods was not statistically significant. Postoperative conditions followed up to over 2 years showed no significant differences on both sides. The establishment of the counterdrainage at the inferior meatus is not necessary considering operation time, blood loss, possibility of nasolacrimal duct injury and early postoperative conditions.