Abstract: The use of the nonionic surfactant polyethyleneglycol octyl phenyl ether (OP) as sensitizer in the FAAS determination of microamounts of copper and zinc was studied. As shown by the experimental results,values of absorbance were increased by 70% and 25% for copper and zinc respectively when OP was added. Linearity ranges found were within 1.2 mg·L-1 for copper and within 0.6 mg·L-1 for zinc. Five plant samples were analyzed by the proposed method,giving values of RSD′s (n=5) less than 6%. Values of recovery found by standard addition method were in the range of 96.8% to 103.0%.