Novel 4′-[(NR1R2-1-yl)]-propoxy-biaryl-4-carboxamides were designed and synthesized. All compounds were tested for affinity at histamine H 3 receptors. Most compounds were highly potent and selective for human and rat H 3 receptors and selected examples such as A-349821 showed functional antagonism of H 3 receptors in vitro and in a mouse dipsogenia model.