Recently, significant progress has been made towards understanding the pathogenesis of cancer from the molecular standpoint. To this end, a growing number of approaches are being exploited for the identification and validation of new therapeutic targets suitable for potent and specific intervention. The type 1 insulin-like growth factor receptor (IGF-1R) system has recently become the focus of major attention in the arena of cancer research. The involvement of the receptor and its downstream signaling cascades in the carcinogenesis process makes this system an excellent target for potential cancer therapy. Indeed, advances in the understanding of the molecular mechanisms behind IGF-1R activation have led to the discovery of agents designed selectively for targeting IGF-1R. The potential application of these inhibitors is currently under intense clinical investigation. This review describes the biology of IGF-1R particularly from a cancer perspective. The attempts to develop effective IGF-1R antagonists are discussed comprehensively with special emphasis on antibodies and small tyrosine kinase inhibitors.