The luminescence decay of uranyl fluoride complexes has been studied in broad fluoride concentration range. Biexponential decay were found with a shorter lifetime component varying between 1.7 and 19.1 mu s, while a longer component is in the range from 49 to 156 mu s The fluoride saturated solution exhibits single exponential decay with a lifetime of 207 mu s. The activation parameters for the decay of [UO2F](+) complex have been determined. The results have been compared to other studies and interpreted in terms of ligand exchange, which is proposed as a new deactivation pathway for excited uranyl fluoro complexes. (C) 1998 Elsevier Science S.A.