Florida has the most species of introduced and established reptiles in the world. There are more species of non-native lizards reproducing in Florida than native species. Tupinambis merianae (Argentine Black and White Tegu) is established in parts of Hillsborough and Polk counties, FL. No evidence of reproduction has been published in other areas of Florida, although this species has been sighted in various other Florida locations, especially in southeastern sites. Using radio-telemetry, we tracked an adult female tegu in Miami-Dade County to a ruderal thicket with a suspected nest mound. Upon excavation of the mound, we found one clutch of 21 eggs from the current year, and one clutch of 22 hatched egg shells and 13 unhatched eggs from a past year. This is the first evidence confirming expansion of a reproducing population of Argentine Black and White Tegus into southeastern Florida. If this population is small and localized, there is potential for removal if swift, decisive action is taken.