Between September to October ]985, 61 male patients with uncomplicated genital gonorrhea, including 33 PPNG urethritis, were treated with single oral dose of rosoxaci, a new oral quinolone derivative, 300 mg Fifty-three patients returned for a test of cure 3 5 days after the treatment. When a patient was found to be not cured, a second course of treatment was given and followed as above. The overall failure rate of initial treatment was 11. 3%(6/53). It was 15. 2%(5/ 33) for ]PPNG urethritis and 5%(1/20) for non-PPNG urethritis. During the course of this trial the rate af PPNG among pretreatment isolates was exceptionally high(62. 2g) compared to 277. during the period of 198l~4. If the PPNG prevalance rate had been a little lower, for instance 30g the overall failure rate would have been much lower(4. 9% ). When the second treatment was given to the failure cases 4-6 days after the first treatment. The overall failure rate dropped to 3. 8go, 3. 1 7o for PPNG urethritis and 5. 0g for non-PPNG urethritis. Ten patients (2l, 3p,) developed postgoriococcal urethritie. Susceptibility test, with disks containing rosoxacin 5mcg, showed the inhibition zone to be greater than 34mm. Eight patients developed minor side effects: dizziness or gastritis. The rosoxacin, oral dose of 300 mg, regimen gave the best result yet by oral treatment for gonorrheae in recent years in Korea.