Genetic relationships within ureaplasma serovars were investigated by pulsed-field gel electrophoresis (PFGE). One hundred thirteen Ureaplasma parvum isolates and 78 Ureaplasma urealyticum isolates were different from their ATCC serovar type strains and different within the same serovars. The organisms were geographically widespread. No unique patterns were associated with invasive disease. Copyright © 2011, American Society for Microbiology. All Rights Reserved.