The invention provides crystalline forms of the novel benzimidazole-carboxamide 5-HT4 receptor agonist compound, 4-(4-{[(2-isopropyl-1H-benzoimidazole-4-carbonyl)amino]methyl}-piperidin-1-ylmethyl)piperidine-1-carboxylic acid methyl ester. The invention also provides pharmaceutical compositions comprising the crystalline compound, methods of using the compound to treat diseases associated with 5-HT4 receptor activity, and processes useful for preparing crystalline forms of the compound.