BACKGROUND To evaluate the results of penetrating keratoplasty (PK) in bullous silicone oil keratopathy (BSK). METHODS PK for BSK was performed in 13 patients, aged from 31 to 82 years. In all patients, pars plana vitrectomy (PPV) with silicone oil implantation (SOI) had been previously performed as the definitive surgery: for complicated retinal detachment with advanced proliferative vitreoretinopathy in 12 eyes and for diabetic traction detachment in one eye. Seven patients were monocular. All 13 eyes were aphakic and there was a long-lasting contact of silicone oil with the corneal endothelium. Before keratoplasty, each eye underwent between two and five operations, on average three, for retinal detachment or late complications of SOI. The interval between SOI and PK was from 11 to 79 months. The patients were followed up for 12-52 months. RESULTS At the last follow-up examination, a clear graft was found in 6 out of 13 eyes (46%). The six clear grafts were found in the ten eyes where silicone oil had been removed before keratoplasty. The graft became opaque in all three eyes in which silicone oil had not been removed. Six out of seven eyes with failed grafts atrophied. Visual acuity improved in all six eyes with the clear graft from had movement preoperatively to 0.05-0.25. The decreased visual acuity was caused by irreparable damage to the macula, which resulted from high myopia, proliferative vitreoretinopathy or long-lasting detachment of the macula. CONCLUSIONS PK in BSK was successful only in those eyes in which the attached retina enabled the removal of the silicone oil before the PK. The reattached retina and useful visual acuity before the development of BSK were the preconditions for functional success of the PK.