This study has been conducted to investigate the amount of residual sulfur dioxide for herbal medicines of 30 species which are purchased in 13 different regions (Bonghwa, Busan, Chunju, Jecheun, Kwangiu, Keumsan, Seoul, Taeku, Cheungdu, Xian, Beijing, Tokyo and Osaka). The sulfur dioxide residues were determined in the collected 386 samples by the modified Monier-Williams method. The residues of sulfur dioxide in 386 samples ranged from ND (under detection limit) to 2808 ppm. The sulfur dioxide in Cassiae Semon, Cinnamomi Ramulus, Cervi Cornu, Hoelen, Crataegi Fructus, Artemisiae Argyi Herba, Scolopendrae Corpus, Schizandrae Fructus and Cyperi Rhizoma were detected under the detection limit regardless of the collected regions. The sulfur dioxide residues in herbal medicines collected in domestic regions were relatively lower than those in foreign regions. There are no standards for sulfur dioxide residual limits of herbal medicines in Korea. This results will provide the scientific basis for the standardization of sulfur dioxide residues in Korea Pharmacopoeia.