Amiloride-sensitive epithelial Na⁺ channels (ENaC) play a key role in Na⁺ transport and fluid homeostasis across the epithelia of the kidney, lung, and colon. ENaC is also known to be present in skin (Mauro et al., 2002, Charles et al., 2008) and articular cartilage (Trujillo et al., 1999) although functional evidence for ENaC in articular cartilage is still lacking. In the present study, inside-out patch clamp electrophysiology was used to identify ENaC-like unitary currents in isolated canine articular chondrocytes. Isolated chondrocytes were cultured for 7 to 9 days in Dulbeccos Modified Eagles Medium with 10% Foetal Calf Serum. Recording was carried out on first to third passage cells. Membrane potential (Vm) was calculated as Vm = –Hp–Vj where Hp was the holding potential and Vj the calculated Junction potential. Data is expressed as mean±standard error. Single-channel activity reversed at a membrane potential of -1±5mV (n = 5) in the presence of 196mM internal and 155mM external Na⁺ solutions, indicative of a sodium current (calculated equilibrium potential, E_Na = -6mV). Mean slope conductance of the channel was calculated to be 9±0.4pS (n = 5). The ENaC-like channel activity was inhibited by the sodium-channel blocker amiloride at a concentration of 10µM. ENaC-like unitary currents were seen in approximately 60% of patches and had a mean open probability (P_o) of 0.3±0.06 (n = 3). After application of amiloride, channel P_o decreased by 97±2% (n = 3). This study provides the first single channel electrophysiological evidence of functional ENaC expression in canine articular chondrocytes and supports previously published molecular evidence for the presence of ENaC in chondrocytes (Trujillo et al., 1999).