The little decapitating fly Pseudacteon cultellatus Borgmeier (Diptera: Phoridae) from Argentina was released as a self-sustaining biological control agent against the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae) in Florida to parasitize small fire ant workers associated with multiple-queen colonies. This fly appears to be established at 2 of 5 release sites, but populations still remain very low (≤ 1% of total Pseudacteon flies) and localized more than 2 yr after their release. Further releases of P. cultellatus in the United States should be limited to a few additional sites in different habitats or climatic regions where this fly might be more successful.