Patulin is a mycotoxin mainly produced by Penicillium and Aspergillus. We investigated the incidence of patulin contamination in 179 samples of apple juice and 9 samples of mixed juice (containing apple juice concentrate as an ingredient) commercially available in the Tohoku district of Japan. Patulin was detected in 3 of 143 samples containing domestic fruits and in 6 of 45 samples containing imported products and products produced in Japan using imported apple juice concentrate. Patulin analyses were carried out using high-pressure liquid chromatography with a detection limit of 4 μg/liter. The patulin content of contaminated domestic samples (three samples with concentrations ranging from 6 to 10 μg/liter), imported samples (one sample with a concentration of 15 μg/liter), and domestic samples produced containing imported concentrate (five samples with concentrations ranging from 6 to 9 μg/liter) was lower than the maximum limit of 50 μg/liter currently adopted by many countries, including Japan.