Thirty-four patients with subluxated and posteriorly dislocated intraocular lenses (IOLs) had repositioning, replacement, or removal of the IOL using pars plana instrumentation. Of the 25 cases posteriorly dislocated into the formed vitreous, ten posterior chamber IOLs were repositioned into the ciliary sulcus, one anterior chamber IOL was repositioned into the anterior chamber angle, and eight posterior chamber IOLs were exchanged for anterior chamber IOLs through a limbal incision. In the remaining six cases, the IOL was removed but was not replaced because of concurrent ocular pathology. In nine cases with subluxation of an anterior chamber IOL into a large basal iridectomy, a pars plana approach after vitrectomy was used for repositioning the IOL into the anterior chamber angle. Complications included each of the following: intraoperative retinal dialysis, postoperative extension of a pre-existing subclinical retinal detachment, recurrent subluxation of an anterior chamber IOL, breakdown of chronic cystoid macular edema to form a macular hole, and pseudophakic pupillary block requiring laser iridotomy.