In an organism, various signal pathways take part in both the embryonic and the adult period. Wnt signal pathway is one of them and it: is highly conserved (from Coelenterata to human). Organisms have three kinds of Wnt signal pathways, which are the Wnt/beta catenin pathway (canonical pathway), the planar cell polarity pathway (non-canonical pathways) and the Wnt/calcium (Ca+2) pathway. Wnt signal pathways have crucial roles in the adhesion of self-renewal cells, regulation of target cell gene transcription in the adult period, and the provision of planar polarity, proliferation of cells, differentiation and cell migration in the embryonic period; however, only the Wnt/beta-catenin signal pathway was discussed in our review, because of its relation with cancer. Any mutation, which may happen in molecules that take part in this signal pathway, may cause several kinds of cancer. Especially in the recent years, the relation of Wnt/beta-catenin signal pathways with cancer types and many important diseases often appears in the literature. The data on the Wnt/beta-catenin signal pathway and the molecules that take part in this pathway, which affect the genesis of both cancer and many diseases, will guide our way in the diagnosis and treatment of such conditions. Thus, in our review, the synthesis and secretion of Wnt protein, its relation with the target cell, signal pathway and the biomolecules, which have a key role in this pathway, were discussed in the light of the literature.