A method was developed to determine copper and zinc simultaneously in brass sample using a multiple ion-selective electrode array system and multivariate calibration techniques. The multiple ion-selective electrode array system was consisted of one pH electrode and eight ion selective electrodes which were formed using commercial ionophores and which are mainly sensitive copper and zinc. PCR, PLS1 which are multivariate calibration techniques were used to calibrate the multiple ion-selective electrode array system using five level multivariate calibration design and PCR method was selected as most suitable method. The measurements were performed at pH 10 in ammonia-ammonium chloride buffer. Copper and zinc content of a brass sample were determined by the calibrated multiple ion-selective electrode array system and the composition of brass sample was also determined by gravimetric method. The percentage amount of copper and zinc in brass sample were 64 ± 1 and 26 ± 2, respectively using the gravimetric method. The percentage results obtained in brass samples for copper and zinc were 63 ± 3 and 24 ± 3 by PCR method and 60 ± 5 and 20 ± 7 by PLS1 method, respectively. The obtained results were calculated for a 95% confidence level.