Purpose To analyze and compare the outcomes and complication rates of secondary implantation of flexible, open-loop, anterior chamber intraocular lenses (AC IOLs) and single-piece, scleral-fixated, posterior chamber IOLs (PC IOLs). Setting Departments of Ophthalmology, Gaziantep University Medical Faculty, Research Hospital, Gaziantep, and Inönü University Medical Faculty, Research Hospital, Malatya, Turkey. Methods This study comprised 124 eyes of 113 aphakic patients (61 men, 52 women) with insufficient capsule support who had secondary IOL implantation from January 1997 to June 2001. In Group 1 (n = 73 eyes), a flexible, open-loop AC IOL was implanted and in Group 2 (n = 51 eyes), a single-piece, scleral-fixated PC IOL. The mean follow-up was 34 months (range 6 to 53 months) and took place at several different clinical settings. The mean interval between the initial cataract operation and secondary IOL implantation was 63 months (range 6 months to 12 years). The postoperative outcomes, safety, efficacy, and complication rates were analyzed, and the preoperative and postoperative best spectacle-corrected visual acuities (BSCVAs) were compared. Results The postoperative mean BSCVA was 20/34.8 ± 45.2 (SD) in Group 1 and 20/32.1 ± 33.7 in Group 2; the difference was not significant ( P = .718). A BSCVA of 20/40 or better was achieved in 62 eyes (84.9%) in Group 1 and 45 eyes (88.2%) in Group 2. A BSCVA of 20/25 or better was achieved in 40 eyes (54.8%) and 33 eyes (64.7%), respectively. The difference between the 2 groups was not significant ( P = .472). Complications occurred in 25 eyes (34.2%) in Group 1 and 13 eyes (25.5%) in Group 2 ( P > .05). The most frequent complications in Group 1 were early transient corneal edema, intraocular pressure elevation, cystoid macular edema, hyphema, secondary glaucoma, and iris capture or pupil decentration and in Group 2, suture erosion, a tilted or decentered IOL, fibrin reaction, and vitreous prolapse into the anterior chamber. Conclusions The AC IOLs and PC IOLs were safe and effective for secondary implantation to correct aphakia. Secondary implantation of the scleral-fixated PC IOL seemed to provide a more favorable outcome and a lower complication rate than the open-loop AC IOL in complicated cataract cases with inadequate capsule and zonular support. As scleral-fixated PC IOL implantation is technically more difficult than AC IOL implantation, the decisive factor in choosing a secondary IOL is surgical experience. Long-term comparison of both techniques is required.