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To study the effect of drought stress as well as nitrogen deficit on sap protein in maize leaf an experiment was conducted in the two locations of College of Agriculture, Tarbiat Modarres University and Kermanshah Razy University. The experimental design was a split-factorial with treatments organized in a randomized complete block design of three replications. Four levels of drought stress (drought stress at vegetative stage = I1, reproductive stage = I2, both vegetative and reproductive stages = I3 and without stress or control = I4) were randomly assigned to the main plot units. A combination of two levels of nitrogen fertilizer (400 and 200 kg/ha) as well as two maize varieties (S. C. 647 and T. C. 647) were assigned to the subplot units. The results indicated that drought stress at vegetative stage reduced leaf sap protein. Drought stress at reproductive stage changed leaf sap protein and protein content in I2 and I3 more than I4 and I1 treatments, while leaf sap protein content became relatively equal in all irrigation treatments at the beginning of second stress stage. Soluble protein was more than in adequate nitrogen treatments than deficit nitrogen treatments. T C 647 variety had more leaf protein content than S. C. 647 in the beginning of stresses, but at end of stress stages, S. C. 647 variety had more leaf sap protein than T C 647 variety. Electrophoresis gel study at vegetative stress showed that protein bounds with 103.3, 52.8, 14.2 and 4.6 Kda molecular weights were omitted in comparison with control. After reproductive stress also protein bound with 89.2 Kda molecular weight were appeared in I2 and I3 treatments and protein bound with 21.6 Kda were observed in I1 treatment. Protein bound with 35.2 Kda molecular weight was weak in I4 treatment in comparison with control. Different protein bounds between varieties and application nitrogen levels were not observed.