This study was undertaken to determine whether there was a correlation between fine particles (PM2.5) levels and hospital admissions for ischemic heart disease (IHD) in Taipei, Taiwan. Hospital admissions for IHD and ambient air pollution data for Taipei were obtained for the period from 2006–2010. 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. For the single pollutant model (without adjustment for other pollutants), increased IHD admissions were significantly associated with PM2.5 on both warm (> 23°C) and cool days (< 23°C), with an interquartile range increase associated with a 12% (95% CI = 10%–14%) and 4% (95% CI = 2%–6%) increase in IHD admissions, respectively. In the two-pollutant models, PM2.5 remained significant after the inclusion of SO2 or O3 both on warm and cool days. This study provides evidence that higher levels of PM2.5 increase the risk of hospital admissions for IHD.