Dopamine (DA) is one of the naturally occurring catecholamines. In the brain, dopamine functions as a neurotransmitter. Its main function as a hormone. Extreme abnormalities of DA concentration levels may lead to several diseases such as Schizophrenia and Parkinson’s. The development of methods for dopamine quantification in blood and biological fluids is the subject of intense current investigation. In this work the electrochemical behavior of the modified electrode was studied by cyclic voltammetry. In part one the modified electrode (Cu(II)) used for determinate of DA. Under the optimum conditions (pH=5.0, scan rate = 90.0 mvs -1 ) calibration plots were found to be linear in the range 1.0 × 10 -7 to 1.0 × 10 -6 M (r 2 = 0.9925) and 1.0 ×10 -6 to 1.0 × 10 -5 M (r 2 = 0.9922); The detection limit was 3.4×10 -8 M, and reproducibility of (R.S.D.? 3.9%). In part two the modified electrode (Ni(II)) used for determinate of DA. Under the optimum conditions(pH=6.0, scan rate = 20.0 mvs -1 ), calibration plots were found to be linear in the range 7.0 × 10 -7 to 7.0 × 10 -6 M (r 2 = 0.9984) and 7.0 × 10 -6 to 1.0 × 10 -4 M (r 2 = 0.9972); the detection limit was 2.0×10 -7 M, and reproducibility of (R.S.D.? 2.9%)