ABSTRACT: Our goal was to develop a list of genes that could be used effectively to highlight the genomic profiling of human embryonic neural stem cells (hENSCs), and to identify genes involved in the process of their differentiation to dopaminergic (DA) neurons. Our results showed that Agilent's Whole Human Genome Oligonucleotide Microarray permits the monitoring of at least 41000 genes as cells differentiate. In this study, we identified 13525 genes to be differentially expressed between undifferentiated hENSC and DA cells isolated from human substansia nigra. Approximately 3737 genes were up-regulated in the embryonic NSC, and 4116 genes were up-regulated in DA cells. Careful analysis of the emerged data using the web-accessible program named Database for Annotation, Visualization and Integrated Discovery (DAVID) has permitted us to distinguish several genes and pathways that are involved in dopaminergic differentiation, and to identify the crucial signaling pathways that direct the process of differentiation. Our study elucidated that genes related to midbrain development, such as Nr4a2 (nuclear receptor subfamily 4, group A, member 2, Nurr1) and En1 (engrailed 1), were increased to 3.76- and 6.41-folds, respectively. In addition, the transcriptions of the genes for DA neuron phenotype, such as Ddc (doapmine decarboxylase, AADC), Slc6a3 (solute carrier family 6, member 3, DAT), and Th (tyrosine hydroxylase), were significantly increased to 8.08, 4.01, and 5.91, respectively. As data accumulate with different populations and different methods of differentiation, one will perhaps be able to identify the key regulators and biomarkers that may allow selective selection of limited number of genes or transcription factors to be used for direct reprogramming of NSC into DA cells, with an ultimate goal of obtaining different types of allogenic neurons including personalized DA neurons to be used in replacement therapy for neurodegenerative diseases such as Parkinson's disease (PD).