We report an unusual case of T-cell lymphoma presenting as ascites. A 72-year-old HIV-negative woman was admitted to our hospital for abdominal discomfort associated with increasing abdominal girth over the course of 1 month. Physical examination showed a tense and distended abdomen and edema of the lower extremities. There was no hepatosplenomegaly or lymphadenopathy. A computed tomographic scan of the abdomen and chest showed massive ascites and pleural effusions, but there was no evidence of tumor masses or lymph node enlargement. The cytospin prepared from the peritoneal fluid was hypercellular and composed of a population of monotonous, large cells containing fine chromatin. No herpesvirus-8 (HHV-8) DNA was detected by polymerase chain reaction in the cells. Immunohistochemistry showed the neoplastic cells to be CD3+, CD4, CD7+. CD8-, CD34-, CD56, and TCR-alphabeta+. Repeated cytogenetic studies showed common abnormalities of del(1) (p11p22), +i(7)(ql0), and t(11:14)(q23;q11). The morphologic and immunologic findings were suggestive of peripheral T-cell lymphoma (PTCL), unspecified. This case suggests that some PTCLs with clonal chromosomal aberrations can exhibit peculiar serosal spreading in the absence of HHV-8 infection.