The first reported case of a non-native termite species being introduced and established in California was the Formosan subterranean termite, which was discovered in San Diego County in 1992. Because this termite can exact tremendous damage within a relatively short time, the affected area was defined and an attempt was made to eradicate it. Intensive baiting with the insect growth regulator hexaflumeron over 12 months appears to have eliminated the original infestation. New infestations have recently been discovered in and around homes about 1/4 mile away, and winged Formosan subterranean termites have been caught nearly 3/4 mile away. Measurements of workers and soldiers and dating of damage suggest that the new colonies are 6 to 8 years old, and that new colonies established from winged reproductives before baiting took effect at the original site. If left unabated, this pest may become increasingly more serious in California.