[en] Annealing studies of fission tracks in sphene from Vaermland (Sweden) in a temperature range of 600⁰C to 495⁰C have been made separately for spontaneous (fossil) and induced (recent) fission tracks. Results include annealing characteristics of the number densities of fission tracks, of the maximum track length (horizontal projection) and of the average track length (horizontal projection). In conjunction with the annealing studies the corrected fission track ages and the corresponding temperatures of sphene samples from Felbertal (Hohe Tauern) and Amstal (Lower Austria), both Austria, have been determined. Relevant geological implications are discussed. (Auth.)