In experimental models of central nervous system (CNS) aging, injury and disease, administering human umbilical cord blood (HUCB) cells induce recovery, most likely by interacting with multiple cellular processes. The aim of this study was to examine whether the HUCB cells produce trophic factors that may enhance survival and maturation of hippocampal neurons in an in vitro test system. We co-cultured the mononuclear fraction of HUCB cells with hippocampal neurons isolated from either young (7-months of age) or aging (21 month of age) rat brain for 14, 21, 28, 35 and 42 days in vitro (DIV), respectively. Immunocytochemistry was then employed to identify neurons (MAP2(+)) and glial cells (GFAP(+)) as well as arborization of neurites. The average number of MAP2(+) hippocampal neurons cells in both young and aging neuronal-HUCB co-cultures was significantly higher than in the control cultures (hippocampal mono-cultures). These MAP2(+) neurons in co-culture were richly arborized, especially in 21 and 28 DIV co-cultures, and expressed functional enzymes (Synaptophysin, tyrosine hydryoxlase (TH)), gamma amino butyric acid receptor (GABAAr) and glutamate transporter (EAAC1). The majority of hippocampal neurons in both co-culture systems grew very well and survived for up to 42 DIV with an increment of immature neurons which were positive for Nestin and TuJ1. Using a multiplex protein array, a number of secreted proteins that could have trophic effects on the neurons were identified.