In our study, it was aimed to investigate the effects of cefazolin, cefuroxime, and cefoperazon injected to rats on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzyme activities in the heart, brain, eye, liver, and kidney tissues of rats. Liver AChE activity at the 1st and 3rd hours of cefuroxime groups was higher than the control group at the same time (p <.05). The AChE activity of the heart tissue decreased in the cefazolin group compared to the control group at the same hour, whereas it increased in the cefuroxime group (p <.05). AChE activities of kidney tissue of cefazolin and cefuroxime groups were lower than those of the same control group on the 3rd and started to increase on the next hours (p <.05). BChE activity is measured in tissues increased within the first three hours and decreased significantly within the first hour in the cefoperazone group (p <.05).