GnRH hormone is important in both male and female reproduction. Chemical agents are preferred to prevent fertility in some animals. Trace elements play an important role in reproduction. In this study, it was aimed to investigate the changes in macro- and trace element levels in blood plasmas of 6th and 12th months of GnRH vaccination (Repro-Bloc (TM)) male rats. 50 male Wistar Albino rats were used in the study. Each rat in the experimental group was administered a single 200 mu l intramuscular dose of GnRH. The levels of Cu, Fe, Mn, Zn, Se, K, P, Ca, and Mg elements were determined by analyzing the collected plasma samples using inductively coupled plasma-optical emission spectroscopy (ICP-OES).