Background: Ivermectin may affect the levels of cytokines and immunoglobulins in sheep, considering that avermectins have an effect on the immune system. Objective: To determine whether ivermectin has an effect on cytokines and immunoglobulins in sheep. Methods: After administration of ivermectin to 10 healthy sheep, sheep-specific interferon-α, tumor necrosis factor-α, interleukin-2, interleukin-6, interleukin-10, immunoglobulin G, immunoglobulin M, and immunoglobulin E levels were measured with an ELISA reader. Results: Significant (p