Neuronal marker proteins are widely used for characterization and identification of normal and tumor tissue of the central nervous system, but the most commonly used neuronal markers have inherent methodological problems. We used a proteomic approach with two-dimensional (2-D) gel electrophoresis and subsequent MALDI identification to identify possible new marker proteins in the human cortical neuronal cell line HCN-2. We found 14 proteins that previously were predicted only on the basis of open reading frames from mRNA sequences or DNA. We could unambiguously identify the following proteins: Bab55091, BK65A6.2 (Novel Sushi Domain (Scr repeat), glucosidase II alpha subunit, glucosidase II precursor (KIAA0088 protein), HSPC108, hypothetical 35.8 kDa protein, hypothetical 40.7 KDA protein, hypothetical 49.4 kDa protein, leucine-zipper protein FKSG13, lysophospholipase homolog, mitofilin (fragment), P1.11659_4, reticulocabin precursor and one unknown protein for MGC:10432. We could prove the existence of these 14 proteins in the human neuron, extending the list of proteins with neuronal expression and identify possible new candidate marker proteins.