A series of 5-chloro-N-aryl-1H-indole-2-carboxamide derivatives were prepared and evaluated as inhibitors of humanliverglycogenphosphorylase a (hLGPa). One compound, 5-chloro-N-[4-(1,2-dihydroxyethyl)phenyl]-1H-indole-2-carboxamide (2f), inhibited hLGPa with an IC(50) of 0.90microM. The pyridine analogue of 2f showed inhibitory activity of glucagon-induced glucose output in cultured primary hepatocytes