Gas exchange and leaf water relations were studied on attached and excised oil palm fronds. Excised palm fronds experienced water stress and responded by closing their stomata in an attempt to avoid water loss through transpiration. This inhibited the diffusion of CO2 into the leaf, decreased the intercellular CO2 level and resulted in a reduction in photosynthetic rate. Water deficit develops in the excised tissue as the demand by transpiration exceeds the supply of water. The leaf water potential (ψl), leaf osmotic potential (ψs) and leaf turgor potential (ψp) were reduced in response to the disruption in water supply. Results show that gas exchange measurements on excised fronds must be carried out immediately after excision in order to avoid water stress effects.