This report describes the isolation of CMV-like viruses from olive, yellow and chacma sub-species of baboons. The viruses were identified as CMVs by their characteristic growth properties in cell culture, virion morphology under the TEM, and antigenic cross-reactivity with other primate CMVs. The glycoprotein B gene homologue from an olive baboon CMV isolate (BaCMV OCOM4-37) was identified, cloned and sequenced. We present the sequence of this gene and by phylogenetic analysis demonstrate that BaCMV is in fact a cytomegalovirus, and is more closely related to rhesus CMV than to human CMV. An ELISA was developed to measure anti-BaCMV antibodies in baboon sera. Serological testing of colony-bred and wild-born baboons indicated that BaCMV is ubiquitous in all baboon populations, with >95% of adult baboons of all sub-species being infected.