Background/Aims: Beta-adrenoceptor is considered to be an important modulator of smooth muscle function. It is widely present in the mammalian gastrointestinal tract and nervous system. The aim of this study was to explore the expression of beta-adrenoceptors (beta 1-AR, beta 2-AR, beta 3-AR) in sling fibers and clasp fibers from human lower esophageal sphincter (LES). Methodology: Sling and clasp fibers from the LES were obtained from patients undergoing esophagogastrectomy; circular muscle strips from the esophagus and stomach were used as controls. Reverse transcription-polymerase chain reaction and western blotting were used to determine the expression of the three sub-types of beta-adrenoceptors. Results: Messenger RNA and protein for three subtypes of beta-adrenoceptors were all identified in the sling and clasp fibers of the LES. Expression was highest for beta 3-AR, then beta 1-AR and beta 2-AR in decreasing levels. Conclusions: beta 1-AR, beta 2-AR, beta 3-AR can be detected in human lower esophageal sphincter and contribute to LES function.