This study was undertaken to determine whether there was a correlation between air pollutant levels and hospital admissions for myocardial infarction (MI) in Taipei, Taiwan. Hospital admissions for MI and ambient air pollution data for Taipei were obtained for the period 1996-2006. The relative risk of hospital admissions was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant models, on warm days (>23¡C) statistically significant positive associations were found for all pollutants except sulfur dioxide (SO2). On cool days (<23¡C), all pollutants were significantly associated with increased MI admissions except SO2. For the two-pollutant model, ozone (O2) and nitrogen dioxide (NO 2) were significant in combination with each of the other four pollutants both on warm and cool days for higher admissions for MI. This study provides evidence that higher levels of ambient air pollutants increase the risk of hospital admissions for MI. 2010 04 15. Copyright © Taylor & Francis Group, LLC.