The author evaluated a group of patients treated on account of carcinoma of the larynx in 1958-1977 and followed up till 1988. A second primary tumour except to that of the larynx and skin was detected in 1978 in 5.5% of the patients, in 1983 in 10.0%, and in 1988 in 12.6%. Before the complete extinction of the group due to deaths of its members it may be assumed that multiple tumours will reach 17%. 44% of the multiple tumours were carcinomas of the lungs and 43% carcinomas of the digestive tract. Follow-up of patients after treatment of carcinoma of the larynx must concentrate attention among others also on organs with a high probability of tumour multiplicity.