Bone marrow transplantation (BMT) is recognized as a successful treatment for malignant and non-malignant hematological diseases. Thanks to transplantation, the number of long-term survivors has risen and with the improved prognosis a problem of ocular side effects has arisen. We carried out a retrospective study to determine the incidence and etiopathogenesis of ocular complications in a series of young patients undergoing BMT. One hundred children (62 males and 38 females) with a mean age of 7.12 (+/- 3.3) years at the time of BMT (autologous in 66 cases, allogenic in 34) were followed for a mean of 4.2 years (range 2-9). The conditioning regimens preceding BMT induced cytoreductive chemotherapy alone (47 cases) or associated with total body irradiation (TBI) (53 cases) in three or six fractions for a total dose of 10-12 Gy. We examined every child before BMT and subsequently every six months. We did not include patients with ocular complications due to the primary disease. Thirty-three children showed several complications after BMT: 17 had subcapsular posterior cataract in both eyes and eight had tear hyposecretion; one had dramatic fungal panuveitis, four had hemorrhagic complications and five optic disk edema. TBI was significantly associated with the development of subcapsular posterior cataract.