An 80-year-old male was admitted to our hospital because of multiple tumors in October 1989. A pathological diagnosis of non-Hodgkin's lymphoma (diffuse, medium-sized cell type) was made with the histological examination of his biopsied tumors. His clinical stage was stage IV A. Chemotherapy (CHOP) brought him to complete remission. In May 1990, relapse of non-Hodgkin's lymphoma was observed in the neck and both eyes. The diagnosis of uveitis due to involvement of lymphoma cells was confirmed by an aspiration biopsy of left aqueous humor. Complete recovery of his visual acuity was possible with additional chemotherapy, and lymphoma cells in his right aqueous humor were expelled completely, while his cervical tumor remained 1/3 of the original size. He eventually died of pneumonia on December 9th, 1990. Intraocular involvement of malignant lymphoma is rare in comparison with extraocular involvement. Especially, the patient who has only turbid aqueous humor as an ophthalmic sign is very rare. In this paper, we reported a case of lymphoma with intraocular involvement and discussed the mechanisms of infiltration of lymphoma cells into the aqueous humor and the therapy.