To study the efficacy, safety, and feasibility of implantation of a bag-in-the-lens intraocular lens (IOL) in children and babies.Departments of Ophthalmology, University Hospital, Antwerp, Belgium, and the University Hospital, Ljubljana, Slovenia, and a private ophthalmology practice, Oudenaarde, Belgium.Thirty-four eyes of 22 children had implantation of a bag-in-the-lens IOL. The ages ranged from 2 months to 14 years. Congenital cataract was present in 26 eyes, and persistent fetal vasculature (PFV) was concomitantly present in 4 eyes. Fifteen patients had bilateral cataract, and 6 had unilateral cataract.In 3 eyes, the IOL could not be properly implanted. In these cases, secondary intervention was necessary because of early posterior capsule opacification. The mean postoperative follow-up was 17.45 months +/- 17.12 (SD) (range 4 to 68 months). None of the children except those presenting with PFV had anterior vitrectomy during surgery. The optical axis remained clear during the follow-up in all patients who had successful IOL implantation.The bag-in-the-lens implantation technique in children and babies was safe and kept the visual axis clear after cataract surgery. In the near future, 4.0 or 4.5 mm IOLs will be available that may improve the success rate of IOL implantation in the small eyes of babies.