We identified 10 patients who developed cytomegalovirus (CMV) retinitis after HSCT during a 14-year period. The median day of diagnosis of CMV retinitis after transplantation was day 251 (range, days 106--365). CMV retinitis was associated with CMV serostatus of donor or recipient (P=0.01), CMV reactivation before day 100 (P=0.007), delayed lymphocyte engraftment (P<0.05), and chronic graft versus host disease (GVHD; P<0.001). In allogeneic recipients of HSCT who were alive at day 100 after transplantation and had chronic clinical extensive GVHD, the incidence of GVHD was 1.4% (8 of 577). Five of 10 patients had other manifestation of CMV disease before retinitis occurred (4 with gastrointestinal disease and 1 with interstitial pneumonia; median time, 70 days before onset of CMV retinitis; range, 58--279 days), and 4 others had CMV excretion. CMV retinitis was bilateral in 4 patients; 9 of 10 patients had ocular symptoms (i.e., decreased vision and floaters). Six of 7 patients responded well to ganciclovir or foscarnet systemic treatment, 1 improved only after switching to cidofovir, and 1 patient who received a transplant in 1983 did not respond to acyclovir treatment. In conclusion, CMV retinitis is an uncommon late complication after HSCT that occurs mainly in seropositive allograft recipients with previous CMV reactivation and chronic GVHD, and with delayed engraftment of lymphocytes.