The existence of familial carpal tunnel syndrome (FCTS) as a separate autonomic entity has been discussed during the last few years. In order to contribute with more data to the literature, we report here the results of clinical. electrophysiological, pathological and radiological studies performed in 5 patients belonging to the same Finnish pedigree. The disease appeared usually before the second decade with numbness and pain on the I--III digits. In most patients symptoms were unilateral but within 2 years they became bilateral. In all patients typical electrophysiological features of median nerve entrapment have been recorded. X-rays of the wrist showed narrow carpal tunnel in all patients. In all patients the possibility of having HNPP as well as familial amyloidosis has been excluded by molecular genetic and pathological studies. All patients underwent surgery and at postoperative stage symptoms were relieved or completely disappeared. Our study supports the theory that FCTS exists as a separate autonomic entity, therefore it is important in front of a sporadic case to investigate the family occurrence of CTS.