The epidemiological situation of HIV infection and AIDS in Navarre in 2003 is reviewed. Up until December 2003, 1,610 HIV infections had been diagnosed in residents of Navarre, of whom 41% had died. The new diagnoses of HIV fell by some 81% between 1993 and 2003, a year in which 28 cases were diagnosed (4.8 per 100,000 inhabitants). The fall basically occurred in infections in injection drug users, since the cases due to sexual transmission had remained stable. Over half of the infections diagnosed in the period 2000-2003 (58%) were attributable to heterosexual transmission, 18% occurred in parenteral drug users and 12% in homosexual men. Thirty-three percent were persons originally from other countries. The incidence of AIDS fell from 75 cases in 1996 to 20 in 2003, and mortality from 65 to 8 cases, respectively. In the 2000-2003 period, the average annual incidence of AIDS was 4.2 per 100,000 inhabitants and the average annual rate of mortality was 1.6 per 100,000 inhabitants. At the end of 2003, there were 902 living persons with a diagnosis of HIV monitored by the health system (1.6 known infections per 1,000 inhabitants). In 2003, 65% of the youths aged between 15 and 29 referred to coital sexual relations, a higher percentage than in previous years, but their level of information on the prevention of AIDS was acceptable. It is necessary to insist on prevention and to adapt this to the new situation.