Fifteen patients with melanocytic proliferative disease of the conjunctiva were treated in part by cryotherapy. In all cases nodules of invasive malignant melanoma were removed surgically if they were present, and cryotherapy was delivered to the base of surgical excision, as well as to surrounding areas of flat pigmentation consisting of intraepithelial melanocytic proliferation. Four patients with focal nodules of invasive malignant melanoma surrounded by minimal to moderate amounts of intraepithelial flat pigmentation appeared to have complete arrest of their disease from six months to 21h years of follow-up. Five patients with preinvasive disease (intraepithelial atypical melanocytic hyperplasia) have had follow-ups of three months to two years (median of 11h years); two patients appear to have had complete arrest of their disease; and three others with very extensive disease have persistent pigmentation and will require additional cryotherapy. With the exceptions of one patient who experienced severe corneal complications leading to a profound loss in vision, and another with progressive bilateral senile macular degeneration, the others have maintained the same vision after operation that they had before cryotherapy. Three patients in this group experienced mild ptosis, two loss of cilia due to eyelid margin involvement, two reversible iritis, and one mild symblepharon formation from forniceal disease. The patient with corneal scarring also developed a cataract. Six patients had widespread flat pigmentation of the conjunctiva associated with one or more nodules of invasive malignant melanoma. Three patients appeared to have complete arrest of their disease, and three others have had evidence of persistent melanocytic activity, with follow-ups of three months to three years (median of one year). The preoperative and postoperative visual acuities have been the same. More severe symblepharon formation was encountered in these patients because of forniceal surgery (four patients), mild ptosis was encountered in one and severe ptosis in three; these patients were more apt to have pupillary and precorneal tear film abnormalities from damage to the ciliary body and accessory lacrimal glands respectively (three patients each). Recurrences in both the preinvasive diffuse and widespread malignant melanoma groups were frequently due to incompletely treated intraepithelial disease, as well as to the impossibility of treating all areas in one cryotherapy session, so that healing usually involved the migration of atypical melanocytes from untreated areas to treated ones. None of the patients has developed deeply invasive disease such as two-thirds of them had at the time they presented, and none of the patients has experienced regional or distant metastases. By adding cryotherapy to the removal of invasive nodules, none of the patients required exenteration.