Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae), a highly polyphagous species, has since the 90's been an important pest of ornamentals and tropical crops in the Canary Islands. In this study the RAPD-PCR technique was used to study the genetic structure of this whitefly in this archipelago. A total of 68 different bands were scored in seven populations using six primers for amplification. No differences in RAPD patterns were found among populations from different islands of the Canaries. These findings indicate a very high genetic similarity among populations and low level of genetic variability and support a single colonization event by few A. dispersus whiteflies and recent dispersion throughout the archipelago.