Extensive corneal disease secondary to microbial keratitis can result in frank or impending corneal perforation requiring a large penetrating keratoplasty. In an 8-year period, 26 penetrating keratoplasties with recipient beds of > or = 9.5 mm were performed on 22 eyes: 11 for bacterial keratitis, 10 for fungal keratitis, and one for a mixed bacterial and fungal keratitis. The graft failed in 18 of 19 eyes (94.7%), with a median time to failure of 12.9 weeks in bacterial keratitis and 4.0 weeks in fungal keratitis. After large keratoplasty, 17 of 20 eyes (85.0%) maintained the structural integrity of the globe. The remainder became phthisical or required enucleation. With preservation of the structural integrity of the globe, a subsequent smaller optical penetrating keratoplasty is an option in some of these eyes.