Ocular manifestations can be the presenting symptom of hematological diseases. Ocular changes can be found in up to 90% of the patients depending on the underlying disease. Most patients with ocular manifestations however are asymptomatic. Hematological disorders can manifest in all structures and adnexa of the eye. The most common manifestations are conjunctival pallor and hemorrhages, intraretinal hemorrhages and cotton wool spots. Retinal infiltrates, manifestations in the lids, anterior segment, optic nerve, orbit and adnexa are rare. Different ocular manifestations in anemia, leukemia, malignant Non-Hodgkin lymphoma, Hodgkin's disease, chronic myeloproliferative diseases, plasmocytoma, myelodysplastic syndromes, coagulopathies, and reticulo-histiocytic diseases are described. Not only the underlying disease but also chemotherapy, bone marrow transplantation can lead to ocular complications.