Abstract: The fully expanded new (FEN) leaves of grapevines (Vitis vinifera L.) appeared to be most sensitive to shading and A and gs increased by 55 and 20 percent respectively, with in 30 minutes. This response was reversed when the shading was removed. Old and new leaves showed similar responses to change in light intensity. The progressive declines in gs and A was observed during the day in all leaf positions. The A:gs ratio was lager and Intercellular CO2 concentration (Ci) lower in the FEN leaves than in either the new or old leaves on the canopy.