Mice, rats, and hamsters have been used as models for human lung cancer for several decades. In the past mainly inhalation of tobacco smoke and other carcinogenic substances have been applied to these rodent species. In most instances, lung carcinomas resembling the human counterpart could not be simulated with the exception of urethane-induced murine models. Moreover, rodents easily and spontaneously develop adenomas but not invasive carcinomas. A cystic squamous lesion was induced in some experiments, which has been labeled as squamous cell carcinoma; however, this represents in essence bronchiectasis with squamous metaplasia and dysplasia but never progressed into invasive squamous cell carcinoma. In recent time genetically engineered lung carcinomas in mice became a tool to study carcinogenesis in adenocarcinomas and small cell carcinomas. In this chapter we will discuss the progress as well as drawback of these different approaches in understanding human pulmonary carcinogenesis.