Pyrrolizine derivatives constitute a class of heterocyclic compounds which can serve as promising scaffolds for anticancer drugs. The unique antitumor properties of mitomycin C inspired chemists to develop different pyrrolizine systems and assess their potential antitumor activities against a wide variety of cancer types. Here we review the different classes of pyrrolizines that possess anticancer potency, with an emphasis on their structure activity relationships, in an effort to pave the way for further development in this promising area of research.