Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) is an invasive pest that has been recently introduced to the Caribbean. It poses a significant economical threat to US agriculture and trade. S. dorsalis is a polyphagous pest that is widespread in habitat ranging from temperate to tropical climatic regions in Pakistan, Japan, and Australia. It is an economically important pest of chili pepper, castor, cotton, onion and other crops with a potential for heavy crop loss. Traditional morphological identification of S. dorsalis requires slide mounting of specimens and familiarity of distinct characters visible through microscopic examination. The accurate identification of pest species is critical in pest management programs. Molecular-based methods provide a means for accurate identification of species such as S. dorsalis . A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach previously developed by researchers has been used to identify certain thrips species including S. dorsalis at our laboratory. In this study, polymerase chain reaction (PCR) and DNA sequencing are utilized for developing species-specific markers for S. dorsalis as well as for elucidating population structure. DNA sequence data has been analyzed from a region of the mitochondrial gene, Cytochrome Oxidase I (COI), and from the Internal Transcribed Spacer 2 (ITS2) region of ribosomal DNA. Development and testing of potential species-specific PCR-primers is underway. A species-specific diagnostic for S. dorsalis would facilitate the development of real-time PCR assays which may provide a fast and reliable method for the identification of S. dorsalis .