In the present study we investigated the content of 5-bromo-2-deoxyuridine (BrdU) in native and fragmented DNA, the activity of caspase-3, and internucleosomal DNA fragmentation in the cerebellum, hippocampus, and cerebral cortex of adult rats at 24 hours, 14 days, and 30 days after BrdU administration. BrdU was used as a marker of neurogliogenesis, and caspase-3 activity and internucleosomal DNA fragmentation were used as markers of apoptosis. The differences in the time course and expression of the markers of neurogliogenesis and apoptosis were revealed in the brain structures studied. The correlation between the processes of proliferation, differentiation, and programmed death of “new” and “old” cells in the adult brain was found. A hypothesis about the structural and functional relationship between neurogliogenesis and apoptosis was discussed.