In humans and cats, muscle from the lower esophageal sphincter (LES) circular region exhibits greater spontaneous tone than LES sling muscle, whereas the sling muscle is much more responsive to cholinergic stimulation. Despite physiological and pharmacological evidence for the presence of L-type Ca²⁺ channel (I_Ca,L) activity in LES circular muscle, the identity of this channel has not been demonstrated electrophysiologically or biochemically. Furthermore, there is no information of the channel's presence and role in the sling region of the LES. We hypothesized that regional differences in the expression of I_Ca,L between LES circular and sling muscles, if present, could contribute to the functional asymmetry observed within the LES. I_Ca,L expression was compared between circular and sling regions of the LES by Western blots. Patch clamp technique was utilized to study I_Ca,L current. Muscle strip studies assessed I_Ca,L contribution to contractile activity. We found both protein expression of I_Ca,L and I_Ca,L current density to be greater in LES circular muscle than sling muscle. I_Ca,L voltage- and time-dependent activation and inactivation curves were similar in cells from both regions. I_Ca,L blockade with nifedipine inhibited spontaneous tone and acetylcholine (ACh)-induced contractions only in circular muscle, but was able to abolish depolarization (KCl)-induced contractions in both sling and circular muscles. In contrast, La³⁺ inhibited tone and ACh-induced contractions in muscles from both regions. Therefore, regional myogenic differences in I_Ca,L expression within the LES circular and sling muscle exist and provide one explanation for the differential contribution of sling and circular muscle to LES contractility.