The synthesis of novel substituted 3-aralkylthiomethylimidazo[1,2-b]pyridazines is reported. All of the synthesized compounds are devoid of antiviral activity against the replication of human immunodeficiency virus. However, compounds 6-chloro-8-methyl-3-phenethylthioimidazo[1,2-b]pyridazine and 6-chloro-2-methyl-3-phenethylthioimidazo[1,2-b]pyridazine are potent inhibitors of the replication of human cytomegalovirus in vitro, while compounds 6-chloro-2-methyl-3-benzylthiomethylimidazo[1,2-b]pyridazine and 6-chloro-2-methyl-3-phenethyl-thioimidazo[1,2-b]pyridazineare inhibitors of the replication of varicella-zoster virus. The results presented here suggest that compound 10 should be considered as a new lead in the development of antiviral agents.