Matrix synthesis by articular chondrocytes is sensitive to changes in intracellular pH (pHi), so characterising the membrane transport pathways that determine pHiis important for understanding how chondrocytes regulate the turnover of cartilage matrix. In the present study, the whole-cell patch-clamp technique has been employed to demonstrate the operation of voltageactivated H+ channels (VAHC) in bovine articular chondrocytes. Using solutions designed to minimise the contribution of ions other than H+, the application of step voltage-protocols elicited whole-cell currents. These currents were slow activating, observed only in the outward direction, dependent on both extracellular pH (pHo) and pHi, and inhibited by Zn2+. The reversal potential values, measured by tail current analysis, over a range of different pHo and pHi values, were in good agreement with predicted values for membrane channels having a high selectivity for protons. The results presented here are consistent with the operation of VAHC in articular chondrocytes.