Ninety leaves of a cotton (Gossypium hirsutum L.) cultivar “Varamin” were randomly selected from, a commercial field. Dry weight, length and width of these leaves were measured for a fast estimation of leaf surface area. Dry weight of leaf was least correlated (r2=O.79) with the surveyed leaf area. Length (L), width (W), L2 and W2 were of equai value (r2 from 0.87 to 0.89) for leaf area estimation. Length by width of leaves (LW) with regression through mean and through origin explained about %96 snd %99 of the variation in actual leaf surface area, respectively Actual leaf surface area of this cotton cultivar might be estimated precisely, fast and nondestructively by multiplying 0.718 by LW.
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