Data on olfactory bulb (OB) development in human fetuses in the stages from the 8th week to birth is provided. Immunohistochemical markers of presynaptic terminals (anti-SNAP-25, synapsin-I, and synaptophysin) were used to evaluate the maturation of the OB. Differentiation of the OB layers begins from the periphery, which indirectly confirms that growth of the olfactory nerve fibers induces not only the anatomical differentiation of the OB but also the differentiation of its functional layers. The sites of the developing glomeruli are revealed using the immunohistochemical procedure prior to the stage in which distinct glomeruli can be identified using a common histological procedure. The OB conductive system demonstrates immunoreactivity with the antibodies to presynaptic proteins at all stages starting with the 10th-11th weeks of fetal development. Four stages of OB development are described. All functional layers of the OB are mature at the 22nd week stage. Further differentiation of the neuroblasts in the OB, including lamina formation of the internal granular layer and the glomerular layer development, and the growth of the OB continue after the 20th-22nd week stage until 38th-40th weeks of fetal development. Patterns of the immunoreactivity with antibodies to SNAP-25, synapsin-I, and synaptophysin at the 38th-40th weeks of prenatal development are fully consistent with those of the adult OB. Complete maturity of the human OB is reached at the 38th-40th week of prenatal development.