BACKGROUND The no-stitch technique has become a standard procedure in cataract surgery in a short time. Nevertheless, it could be necessary--especially when learning this technique--to use a suture to close the wound. PATIENTS In this study we examined 24 patients who needed a suture from April 1991 to July 1993. By using a gonioscope we tried to find the reason for the insufficient self-sealing effect. During this period there were 7,966 cataract operations using the no-stitch tunnel technique, including about 618 eyes with a self-sealing ECCE technique. RESULTS In 13 eyes iris prolapse was found, in 9 eyes low IOP and in 2 eyes exceptionally astigmatism. In 11 eyes the reasons for these complications were that the inner corneal lamella was too small, in 9 eyes this lamella was cut, and in 2 eyes there was a step between this lamella and the inner surface of the cornea. The reason for the high astigmatism in 2 cases was not found in the corneal lamella, but in the scleral one which had shown a defect. The incidence of insufficient wound closure was 0.81% in ECCE (n = 618) and 0.26% in phacoemulsification surgery (n = 7348). CONCLUSION The most common reason for insufficient wound closure in the no-stitch technique is malpreparation of the corneal lamella.