STUDY OBJECTIVE: To determine the influence and the effect of the war in the former Yugoslavia and of the United Nations economic sanctions on mortality from infectious diseases. DESIGN: This was a descriptive study analysing mortality data time series. SETTING: Central Serbia, Yugoslavia. PARTICIPANTS: The population of central Serbia was the subject of the study (about six million inhabitants). MEASUREMENTS: Mortality rates were standardised directly, using the "European population" as the standard. Regression analysis and analysis of covariance were undertaken. MAIN RESULTS: During the period 1973-93, mortality from infectious diseases showed a decreasing trend. From 1987-90, and infectious diseases was significantly higher than expected on the basis of the trend for the preceding period (p = 0.020 and p = 0.00). In addition, there was a statistically significant departure from the preceding trend (p = 0.036) in men between 1991 and 1993 (the period of the war and UN sanctions)--the main effect being in younger age groups. CONCLUSION: The economic crisis in the former Yugoslavia during the 1980s followed by the outbreak of the war and the damaging effects of UN economic sanctions had a distinctly adverse effect on mortality from infectious diseases.