As a result of ongoing systematic study of the genus Chrysotoxum, we have discovered C. ramphostomus and C. tuberculatum for the first time in Korea. These two species closely resemble each other and need to be identified with caution. We here provide detailed redescriptions and illustrations with their diagnostic characters indicated. Chrysotoxum tuberculatum can be readily distinguished from C. ramphostomus by the following characteristics: 1) hind trochanter with small tubercle; 2) compound eyes apparently bare; 3) basal 1/5 of hind femora brownish yellow; and 4) male genitalia asymmetrical in caudal view.