Cataracts, simply defined as a focal or complete opacification of the lens, are the leading cause of vision in purebred and older dogs. Caratacts can be congenital or acquired postnatally, inherited, or caused by disease, toxicity, trauma, or advanced age. Surgery is the only method of restoring vision in patients blinded by cataracts. The development of phacoemulsification in conjunction with the development of the artificial lens has greatly improved the success rate of the surgery, as well as the visual acuity post-operatively. A 3 year old, male castrated chocolate Labrador retriever presented with the chief complaint of vision loss in both eyes. The dog was bright, alert and responsive. He was over conditioned and aside from his vision loss his physical examination was unremarkable. Initial ophthalmic examination revealed that he had bilateral mature cataracts. His eyes appeared slightly microphthalmic and had iris-to-iris persistent pupillary membranes. Preoperative evaluation included hemogram and serum chemistry panel (both normal), electroretinography (normal) and ocular ultrasonography (normal). The opthalmic examination findings and ERG/US diagnostic results suggested his progressive cataracts had been congenital. This paper will briefly explore cataracts, their causes, and their differentiation from nuclear sclerosis. It will also take an in depth look at their surgical treatment by phacoemulsification with introcular lens implantation.