Cell lines have always been a valuable tool to address a variety of questions related to prostate cancer. Due to the unavailability of many human prostate cancer cell line models, investigators have shown significant interest in developing or establishing different new nonhuman prostate cancer cell lines. Indeed, many animal cell line models have successfully recapitulated key events in human prostate cancer development. For instance, Dunning rat prostate cancer cell lines have created a system to represent the full spectrum of prostate cancer progression while canine cell lines like Leo and Ace-1 recapitulate bone metastasis model. The establishment of in vitro models of animal cell lines recapitulating human disease will aid in molecular and functional characterization of human prostate cancer.