Between 1984 and 1990, 16 children who had been treated for a histologically proven head and neck rhabdomyosarcoma developed 19 local recurrences. Fourteen relapses discovered in 11 children (group 1) were based on clinical data acquired 3 to 52 months after completion of treatment. Clinical symptoms (12 patients) or examination (2 patients) led to suspicion of a relapse. The clinical presentation of relapses and that of primary tumour were identical in eight cases. CT scans performed prior to recurrence revealed a stable 'post-therapeutic residue' without mass effect at the original site (12 patients) or was normal (2 patients). Six of these 11 children died at 1 to 15 months and five are alive 12 to 36 months after treatment of recurrence. Five relapses were discovered on CT studies 3 to 15 months after completion of treatment in the remaining five children (group 2). Clinical examination was normal in all cases. CT scans performed 3 months before recurrence showed a stable 'post-therapeutic residue' (4 patients) or was normal (1 patient). All of these five children died 3 to 23 months after the relapse.