Twenty cases of primary non-Hodgkin's malignant lymphoma (ML) of the vagina were studied: the 17 cases reported in the literature, and 3 further cases observed at the Hôtel-Dieu Hospital in Paris over the last 10 years. The mean age of the women was 49 years. The most frequent complaint was vaginal bleeding, only a few patients presented an ulcerated mass. No evidence of ML was seen on any of the cervico-vaginal cytologic smears. Diagnosis was made on the vaginal biopsy. According to the Kiel classification, 8 of these ML were of low malignancy and 12 of high malignancy. Apart from one of our cases, which was an angiocentric pleomorphic T ML with predominance of medium-sized cells, they were all B ML. According to the Ann Arbor staging system for extra-nodal ML, 12 of these ML were stage IE, 2 were stage IIE and 2 other stage IVE. Eight patients died, 6 of ML less than 17 months after diagnosis, 2 much later of diseases unrelated to ML. The mean follow-up period of patients who survived, free of disease, was 75 months. The surgical treatment has to be limited, associated with polychemotherapy and completed by local radiotherapy.