Microarray chips produced by commercial vendors and academic laboratories are mostly generic in nature to facilitate wide applicability. With the sequencing of the human, mouse, and rat genomes, the thrust is to expand clone and oligonucleotide sets and increase the number of genes represented on a particular array. This is appropriate for discovery based investigations where microarray technology has been successfully utilized. However, array technology can also be employed to perform hypothesis based studies if optimized chips can be produced with relevant content. Existing array technology available at core facilities can be effectively utilized to produce a custom microarrays with genes that are most relevant to the research interests of individual investigators or research groups for use as a standard molecular tool. The power of this technology can be harnessed to further our understanding of specific biological problems without involvement in extensive data mining and analysis. The custom microarray approach is presented with procedural details for design and production in the context of neurobiological investigations.