The present invention relates to novel imidazolidinone derivatives thereof, their synthesis, and their use as &agr;v integrin receptor antagonists. More particularly, the compounds of the present invention are antagonists of the integrin receptors &agr;v&bgr;3 and/or &agr;v&bgr;5 and are useful for inhibiting bone resorption, treating and preventing osteoporosis, and inhibiting vascular restenosis, diabetic retinopathy, macular degeneration, angiogenesis, atherosclerosis, inflammation, inflammatory arthritis, viral disease, cancer, and metastatic tumor growth.