30 cases of methemoglobinemia who had been admitted in pediatric department of Busan National University Hospital from Jan. 1970 to Jun. 1976 were clinically studied, and the results were summerized as followings: 1. The incidence of methemoglobinemia was corresponding to 0.5% of all pediatric in patients, and 16.7% of all acute poisoning during same period. 2. The sex ratio of male to female was 2:1 and the peak age group was 1 to 3 years of age. 3. The prevalent incidence in a year was shown in August and in Summer season. 4. The most frequent causative substances of methemoglobinemia was D.D.S(26 cases) and then phenacetine( 2 cases). The motive of poisoning was mianly accidental causes(23 cases) 5. Clinical features of methemoglobinemia was relatively good and this patient was treated with methylene blue and ascorbic acid.