Mesenchymal stem cells exist in many tissues and are known to actively migrate to sites of tissue injury, where they participate in wound repair. Tumours can be considered "wounds that never heal" and, in response to cues from a tumour, MSCs are continuously recruited to and become integral components of the tumour microenvironment. Recently, it has become apparent that such tumour-associated MSCs (TA-MSCs) have an active role in tumour initiation, promotion, progression and metastasis. In this review, we discuss recent advances of association of the MSC and AT-MSC and address in our understanding of the role of TA-MSCs in regulating the survival, proliferation, migration and drug resistance of tumour cells. Moreover, we discuss therapeutic approaches that target TA-MSC upstream or downstream modulators or use MSCs as vehicles for the delivery of tumoricidal agents.