We retrospectively studied secondary intraocular lens (IOL) implantation in 165 aphakic patients (162 eyes) from May 1983 to August 1989. Seventy-five eyes (46.3%) had secondary IOL implantation; these included seven cases of trans-sulcus scleral fixation of the posterior chamber lens. The remaining 87 eyes could not have secondary IOL implantation because of the ocular conditions. The most common reason for secondary implantation was to relieve the discomfort caused by spectacles or contact lenses (56.2%). An anterior chamber lens was used in 43 eyes (57.3%) and a posterior chamber lens in 32 eyes (42.7%). Final postoperative visual acuity of 20/40 or better was achieved in 92.0% of the eyes with posterior chamber lenses, in 71.4% of the eyes with anterior chamber lenses, and in 57.1% of the eyes with scleral-fixated posterior chamber lenses. Endothelial cell loss was greater in the eyes with anterior chamber lenses than in the eyes with posterior chamber lenses. Of the cases that could be followed, 83.3% showed endothelial cell loss of less than 30% at six months postoperatively. Postoperative complications such as cystoid macular edema, persistent fibrinous membrane formation, and neovascular glaucoma occurred in only ten (13.3%) of the 75 eyes that had secondary implantation. These complications occurred more frequently in eyes that had anterior chamber lenses with anterior vitrectomy. There were no noticeable complications in the eyes that had trans-sulcus scleral fixation of posterior chamber lenses. Updrawn pupil, prolapsed vitreous, and peripheral anterior synechia were common conditions preventing secondary IOL implantation.