The insulin-like growth factor (Igf) family is an evolutionarily conserved system essential for normal growth and development in vertebrates. Unlike mammals, four distinct Igf ligands (Igf1, Igf2a, Igf2b and Igf3) and two Igf type 1 receptors (Igf1ra and Igf1rb) are present in zebrafish. However, the localization of these multiple ligands and receptors especially the recently discovered igf3 during early development of zebrafish is poorly understood. In this study, detailed expression patterns of these components of the Igf system during embryogenesis of zebrafish were analyzed. It was found that igf1 is specifically expressed in the trigeminal ganglia region from 18hpf to 72hpf, while igf2a is restricted to the caudal regions of the notochord from 14hpf to 18hpf as well as in the midbrain, dorsal hind brain and otic vesicle at 24hpf. On the other hand, igf2a is highly expressed in the midbrain and pharyngeal arch region at 48hpf, followed by its appearance in the liver and brain at 72hpf, while igf2b is restricted to the floor plate and hypochord from 12hpf to 18hpf, and strong expression is also detected in the midbrain and dorsal hind brain at 24hpf. The teleost specific igf3 is highly expressed in the pharyngeal arch region before 24hpf, but is then restricted to the sternohyoideus after 48hpf. The receptor subtype igf1ra is ubiquitously expressed before 24hpf but is confined to the brain at 72hpf. However, igf1rb is widely expressed before 10hpf, but is more confined to the brain region at 24hpf and 72hpf. This dynamic temporal-spatial expression during embryogenesis of zebrafish, together with the unique and overlapping expression patterns of the Igf ligands and receptors suggest the coordination of the divergent functions of the Igf system during early development in zebrafish.