Ureaplasma urealyticum causes infection or colonization of female genital tracts associated with preterm delivery and infertility and the infection of the bloodstream, respiratory tract, and central nervous system in infants, especially in prematures. We report the first case of U. urealyticum meningitis in a premature infant in Korea. She was born with a birth weight of 1,481 gram at 32+3 weeks' gestation and hospitalized for a respiratory care in the NICU in November 2005. Endotracheal aspirates and urine cultures grew U. urealyticum at <10(4) CFU/mL of the specimens at 2-day-old, and cerebrospinal fluid (CSF) cultures grew U. urealyticum at > or = 10(4) CFU/mL of CSF. The patient had a marked CSF pleocytosis, low glucose and high protein content on the 13th hospital day. CSF cultures for ordinary bacteria, mycobacteria and fungi remained negative. U. urealyticum was resistant to erythromycin, tetracycline, ciprofloxacin and pristinamycin, but susceptible to doxycycline. Although she was treated with erythromycin for 30 days, the organism was still isolated four times from the CSF with fluctuation of C-reactive protein (CRP). After the addition of chloramphenicol, CSF cultures became negative in 3 days. However, CRP rose again with increased BUN at the 99th hospital day, and she died on the 103rd hospital day under the diagnosis of a clinical sepsis of unknown origin. In acute meningitis of prematures already colonized with U. urealyticum, ureaplasmal cultures and susceptibility test are warranted in Korea.