Tissue microarray (TMA) technology is a high-throughput research tool, which has greatly facilitated and accelerated tissue analyses by in-situ technologies. TMAs are amenable to every research method that can be applied on the standard whole sections at enhanced speed. It plays a central role in target verification of results from cDNA arrays, expression profiling of tumors and tissues, and is proving to be a powerful platform for proteomic research. In this review article, primarily meant for students of pathology and oncology, we briefly discuss its basic methodology, applications and merits and limitations.