Results of a clinical study concerning 40 consecutive cases of high post-keratoplasty astigmatism corrected by the transverse keratotomy technique are presented and analysed. The protocol was determined for each case by keratometry and a qualitative analysis of the anterior corneal topography. The mean preoperative cylinder was 8.60 +/- 2.31 D. The mean postoperative cylinder was 4.79 +/- 1.82 D. The mean cylinder change was 4.40 +/- 2.92 D. In a majority of cases the corrected visual acuity (for distance and reading vision) was improved. There was no change in the spherical equivalent value. The main drawback of the procedure is its poor predictability. The procedure is effective in this indication and relatively safe.