A clinical survey of 798 cases of diphtheria, particularly 172 tracheotomized, cases isolated and treated in Seoul Central City Hospital during 15 months from January 1964 to March 1965 is reported and compared with the similar report which we repoted in 1964. The results are as follows : 1) Most of the patients complaining of dyspnea, hoarseness, and barking cough were male(60%) ; 3-4 years of age occupied 25% of all cases ; infected in winter months (Nov., Dec., Jan., and Mar.) in 63.3% of all cases, and laryngeal diphtheria occupied most of them. 2) Skillful tracheotomy was the safest and the most efficient life-saving measurement with less deaths against suffocations due to laryngeal diphtheria. Deaths were 5.2% of all cases.