The folate receptor (FR) is a confirmed tumor-associated antigen that binds folate and folate-drug conjugates with very high affinity and shuttles these bound molecules inside cells via an endocytic mechanism. Using folate (or an analog thereof) as the ligand, a wide variety of drug payloads can be delivered to FR-positive cells, ranging from small radioactive imaging agents up to large DNA-containing formulations. For therapeutic purposes, attachment of small molecular weight, highly potent agents to folate is a novel approach. As such, this review will outline the manner in which folate-drug conjugates are screened preclinically, it will summarize published activity data of various conjugates, and it will also highlight some newly emerging animal data from novel compounds that are currently under preclinical investigation.