Measures to alleviate the growing problem of macrolide resistance in Taiwan resulted in a decrease in macrolide consumption, from 0.629 defined daily doses/1000 inhabitants per day (DIDs) in 1999 to 0.301 DIDs in 2003 (a reduction of 52%). A linear relationship was observed between the decline in erythromycin consumption and the decline in erythromycin resistance in Streptococcus pyogenes (46% in 1999 vs. 17% in 2003; p < 0.001) and azithromycin resistance in Haemophilus influenzae (31% in 2000 vs. 0% in 2003; p < 0.001). However, the rate of erythromycin resistance in Streptococcus pneumoniae showed a continued increase, from 80.2% in 1999 to 92% in 2003.