A newseries of 4-acyl-2-thiazolylhydrazone derivatives was synthesized and screened for its in vitroactivity against Toxoplasmagondii. We evaluated parasite growth inhibition and cytotoxicity, inhibition of replication, and inhibition of parasite invasion of host cells. The biological results indicated that some substances had an antiproliferative effect against intracellular T. gondii tachyzoites