The present invention provides pharmaceutical formulations comprising an antibody that specifically binds to human delta-like ligand 4 (Dll4). The formulations may contain, in addition to an anti-Dll4 antibody, a phosphate buffer, an organic cosolvent, a disaccharide, and a salt. The pharmaceutical formulations of the present invention exhibit a substantial degree of antibody stability after storage for several months and after being subjected to thermal and other physical stress.