the scientific production of Portuguese institutions in the specific field Oncology during a 10 year period (1997-2006) was evaluated. The contribution of national authors to the international scientific production was verified. This enabled to assess and quantify the importance of authors, departments, institutions and scientific investigations.Using version 2006 of Web of Science, section Science Citation Index, a database of literature references which enables analysis of citations, and also the Journal Citation Reports (tools produced by ISI Thomson Scientific), a quantitative and qualitative analysis of the Portuguese scientific production on cancer between 1997 to 2006 was performed.during the studied period, 1.384 articles were published in scientific journals with given impact factor, which obtained a total of 16.484 citations, corresponding to a mean of 11.91 citations per article. Between 1997 and 2006 an increase of 214% was noticed in the national scientific production in the selected field. Ten authors represent 46% of the produced documents. The majority of published articles were performed by Universities, being Oporto University the one with highest contribution. Co-authorship is the rule in the production of articles and Portugal is no exception. Articles with international collaboration where those which obtained the highest citation rate. The Portuguese contribution to the international scientific production in the field of Oncology in the studied period was of 0.21%.Bibliometric analysis is a reliable tool to evaluate the development and quality of scientific production. A growing visibility of investigation in this area was observed. This conclusion is based on the increase in the number of articles published in international journals of recognized reputation. National authors publish few articles, but they select high standard journals.