Primary colorectal lymphomas are rare tumors that comprise 0.5 to 2% of large bowel malignancies and 10 to 20% of gastrointestinal lymphomas. Between 1982-1993 ten patients were treated in the Colorectal Unit of the "Hospital das Clínicas" of the University of São Paulo, representing 2% of the neoplasms in this period. Age varied from 22 to 76 years, with median around 50 years, and male/female ratio 8:2. Weight loss, right iliac palpable mass and bowel habit alterations were the most common symptoms. Definitive diagnostic was only set with histological evaluation of the surgical specimen in all colon tumors. Four patients had advanced disease classified as stages III or IV. The tumors were located in ileocecal region (7 cases), transverse colon (1 case), sigmoid colon (1 case) and rectum (1 case). Colon lymphomas were treated by radical surgical resection and chemotherapy; the patient with rectal lymphoma received radiotherapy and chemotherapy because of local tumor spread. Histological data showed 6 large cell lymphomas and 4 small cleaved cells lymphomas. Lymphnodal involvement and tumor size were the main prognostic factors in the series: 80% of the patients in advanced stage (III or IV) and 66% of those with tumors larger than 10 cm died during the first year of the follow-up.