ABSTRACT BACKGROUND: After penetrating keratoplasty, many patients have high ametropia, which is difficult to correct with contact lenses. We used excimer laser in situ keratomileusis (LASIK) on four eyes of four consecutive patients that had previous penetrating keratoplasty in an attempt to correct myopia and astigmatism. METHODS: We used an automated microkeratome to make a lamellar flap and a Chiron Technolas 193-nm argon fluoride excimer laser. The laser was programmed for the desired myopic and astigmatic correction and a multizone ablation was applied to the central stroma. The corneal flap was placed back into position without sutures. RESULTS: After surgery, all corneas remained clear with no dislocation of the flap, and the edge of the flap was difficult to visualize after a few days. The average preoperative spherical equivalent was -10.75 diopters (D) (range -5.00 to -14.25 D) which decreased to an average -2.37 D (range -0. 75 to -5.00 D) at a mean follow-up of 7 months (range 6 to 10.5 mos). The average preoperative astigmatism was -2.87 D (range -1.00 to -5.00 D) which changed to an average of -3.50 D. Uncorrected visual acuity was improved and spectacle-corrected visual acuity was preserved without changes. CONCLUSION: LASIK can effectively reduce myopia after penetrating keratoplasty. [J Refract Surg 1997;13:27-32]