The determination of ochratoxin A (OTA) was performed using immunoaffinity column for cleanup, HPLC for quantification and chemical derivation and LC-electrospray tandem mass spectrometry for confirmation. The detection limits for coffees, cereals and red wines and beers were 0.1, 0.3 and 0.2 ppb, respectively. The recoveries of OTA from coffees were 97.2 ± 4.9, 97.3 ± 3.1 and 95.4 ± 0.4% at 2, 4 and 8 ppb spiked levels, respectively. Spiked 0.3, 3 and 5 ppb OTA in cereals (mainly rice and wheat based food), the recoveries were 89.6 ± 5.1, 99.6 ± 1.4 and 90.2 ± 1.4%. The recoveries of red wines and beers were 91.9 ± 6.6. 99.4 ± 6.1 and 90.7 ± 0.6% at 0.2, 1 and 3 ppb spiked levels, respectively. In order to survey the OTA contents in daily diet in Taiwan, 51 samples of coffee, 114 samples of cereal (75 were rice or rice based samples and the rest were wheat flour or wheat based samples), and 10 samples of red wine and 18 samples of beer were analyzed. The results showed that OTA was detected in 13 (25%) coffee samples, 5 (50%) red wine samples and 2 (5%) wheat flour and wheat flour based samples at 0.1~0.5 ppb levels. According to the “Nutrition and Health Survey in Taiwan 1993~1996”, the OTA consumption of adults were much lower than the established tolerable daily intake (TDI) of 5 ng/kg bw (European Commission) or tolerable weekly intake (TWI) of 100 ng/kg bw (JECFA)