Abstract: The aim of this research was to investigate SPAD meter readings variations of rapeseed leaves under different treatments. A pot experiment was conducted at a controlled glasshouse in College of Agriculture, Shiraz University, Shiraz, Iran in 2006. Treatments were various rapeseed cultivars (Hayola 401, Hayola 308, Option and RGS) and irrigation regimes (FC (non-stress), 75 FC, 50 FC and 25% FC). The factorial set of treatments was arranged within a randomized complete block design with three replications. The results showed that with increase in drought stress, SPAD meter readings (the relative chlorophyll concentration of leaves) were decreased. Results showed that, drought stress had a significant effect on net photosynthesis (A), stomatal conductance (gs) intercellular CO2 concentration (Ci) and leaf area (LA) of rapeseed at both vegetative and flowering stages. In general, Hayola 401, had the highest yield in both control and drought treatments, followed by Hayola 308, whereas RGS had the lowest yield among the cultivars. Hayola 401 and Hayola 308, had the highest gs in control and the lowest gs in drought treatments. Cultivars tolerance rankings in this study, was Hayola 401, Hayola 308, Option and RGS. Information obtained in this study may be useful for breeders to introduce suitable drought resistant rapeseed cultivars under arid regions.