The development of inducible and conditional technologies allowed us to generate transgenic mouse models that faithfully recapitulate human tumorigenesis. It is possible to control, in time and space, the development of tumors in almost every mouse tissue. The result is that now we have available mouse models for all major human cancers. Novel noninvasive approaches to tumor imaging will enable us to follow tumor development and metastasis in vivo, as well as the effects of candidate therapeutic drugs. Such new generation tumor models, which accurately emulate the disease state in situ, should provide a useful platform with which to experimentally test drugs targeted to specific gene products, or combinations of genes that control rate-limiting steps of tumor development. In this review, we focus on the different mouse models for colon cancer.