Two patients who had undergone radial keratotomy developed delayed postoperative infectious keratitis. Both patients had surgery at the same outpatient facility, and their procedures had been performed by the same surgeon. The corneal lesions appeared similar in both cases, consisting of white irregular infiltrates with radiating projections and fluffy, indistinct margins. Although they were found at all levels, the lesions were most concentrated in the mid-to-deep stroma and were associated with overlying epithelial defects. In both cases, Mycobacterium chelonei was isolated from corneal biopsy specimens. Both patients were treated with topical fortified amikacin; in one there was complete resolution of the corneal infiltrates with medical therapy alone. Although the other patient's lesions initially appeared to resolve with medical therapy, she eventually required corneal transplantation because of recurrence of the infiltrates. Histopathologically, the infiltrates consisted of myriads of acid-fast bacteria with rare inflammatory cell infiltrations.