Background: The first distinctive feature in the development of mammary glands is the apparition of milk lines that is followed by the formation of 5 pairs of the placodes, which outgrowths to form mammary buds. Later, the buds give rise tubular branched structures. These structures represent the primordial of lactiferous ducts, which from 18th day of embryonic development stop to differentiate until the puberty. The major events that occur during the breast development are strongly connected to cyclic hormonal modifications in pregnancy, lactation and menopause. At the puberty occurs the branching of ductal excretory system – a process controlled by a broad spectrum of molecular factors. These are the hormones, growth factors, matrix active substances, metaloproteinases (MMP), and the components of immune system. The aim was to highlight the molecular factors involved in the control of mammary gland development at different embryonic and post-natal stages. Conclusions: Molecular factors, involved in mammary development have diverse pathways and origin. Sophisticated interactions of these factors determine step-like development and permanent rearrangement of the gland. Any disturbance within these signaling pathways may lead to appearance of different pathologies: from morphological abnormalities to malignancies. As a result, understanding of these mechanisms represents a theoretical basis necessary to elaborate a new strategy of diagnosis and therapeutic management of breast carcinoma.