Intraocular lenses were implanted in 16 eves of 13 patients with congenital cataract, and visual progress was plotted using a preferential-looking technique. Initial surgery was by lens aspiration with preservation of the posterior capsule, and subsequent posterior capsulotomy without anterior vitrectomy. Poly-HEMA posterior chamber lenses were used, usually as a primary procedure but in four cases as a secondary procedure after contact lens failure. No serious complications were encountered. Most eyes achieved a very significant visual improvement, and none were worse than preoperatively. Residual refractive error was highly unpredictable, but did not exceed 6 dioptres. The importance of rigorous occlusion therapy is stressed. With close follow-up, this procedure offers an effective and safe method for the correction of unilateral paediatric aphakia, and, in selected cases only for bilateral aphakia.