Three cases of histologically proven primary non-ampullary adenocarcinoma of the duodenum, observed in our Department from 2001 to 2004, are described. The cases were treated by pancreaticoduodenectomy, duodenal resection and transduodenal excision, respectively. The rarity of this pathology is documented by few retrospective studies and justifies discussion about the main prognostic factors and the best therapeutic approach. We analyze diagnostic, therapeutic and prognostic factors after a revision of literature.