There is a few available information about the effect of anesthetics, specially electroanesthesia on immune parameters in fish. In the present work, two anesthetics, MS222 (50 ppm), clove oil (25 ppm), and electroanesthesia were tested in rainbow trout (Oncorhynchus mykiss) in narcosis stage. The results showed, clove oil and electroanesthesia increase the lysozyme activity 24 h after anesthesia(p0.05). It seems use of MS222 during aquacultural practices may induce lesser effect in rainbow trout