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Cytokines such as tumor necrosis factor-α (TNF-α), FasL, and TNF-related apoptosis-inducing ligand (TRAIL) induce apoptosis or inflammation through binding to their specific receptors, TNFR1, Fas, and DR5, respectively. We have previously reported ligand-binding and cell death-inhibiting synthetic peptides, which were designed based on the crystal structure of a ligand-receptor complex and the homology of the amino acid sequence among the death receptor family members. Here we show that, among these death receptor-derived peptides, the TNFR1-derived peptide specifically arrested cell proliferation and promoted cell adhesion of fetal rat (E16) hippocampal cells, and promoted neurite outgrowth from hippocampus-derived neurospheres cultured with the addition of the peptide or cultured on a peptide-coated surface. Furthermore, among these death receptor-derived peptides, marked neurite outgrowth was observed only when the neurospheres were cultured on a TNFR1-derived peptide-conjugated covalently cross-linked alginate gel. The neurites from the neurospheres positively immunostained with an antibody against neurofilaments. These results suggest that the TNFR1-derived peptide promotes neuronal differentiation of the hippocampal neural stem cells and the TNFR1-derived peptide-conjugated covalently cross-linked alginate gel may be a useful material for assisting neural stem cell transplantation.