Caveolins are important structural proteins of caveolae, small invaginations of the membrane. They have been shown to play an important role in the pathogenesis of multiple cancers. In this volume, we will mainly focus on the importance of caveolin-1 in breast, prostate, lung, skin, colon, pancreatic and brain cancers with also a mention of the novel role of caveolin-3 in breast cancer.