Although the zebrafish model provides an important platform for the study of developmental biology, recent work with the zebrafish model has extended its application to a wide variety of experimental studies relevant to human disease. Currently, the zebrafish model is used for the study of human genetic disease, caveolin-associated muscle disease, homeostasis, kidney development and disease, cancer, cardiovascular disorders, oxidative stress, caloric restriction, insulin-like pathways, angiogenesis, neurological diseases, liver disease, hemophilia, bacterial pathogenesis, apoptosis, osteoporosis, immunological studies, germ cell study, Bardet-Biedl syndrome gene (BBS11), Alzheimer's disease, virology studies and vaccine development. Here we describe the essential use of the zebrafish model that applies to several clinical diseases. With increased understanding of the cellular mechanisms responsible for disease, we can use knowledge gained from the zebrafish model for the development of therapeutics.