Abstract: The aims of present research were to determine the concentration of micro minerals, including Cu, Zn, Co and Fe in hydatid cyst fluid, comparing micro minerals composition between fertile and infertile cysts and determining the correlation between values in cysts, serum and liver tissue. A total of 2,550 slaughtered sheep were examined carefully for hydatid cyst infection. Blood samples, hydatid cysts fluid and liver samples were taken from 100 infected sheep and gravidity was diagnosed in aid with microscopic examination. Potentiometric Striping Analyzer (PSA) and atomic absorption spectroscopy were used for measuring the micro minerals concentration as well. Results showed that the concentration of mentioned micro minerals in gravid cyst fluid and its related sheep serum were significantly higher than that non-gravid ones. So, a significant and positive correlation between some micro minerals (zinc, cobalt and iron) concentration of gravid cyst fluid and related sheep serum was observed too (p<0.05).