Immunocompetent individuals can harbor multiple human cytomegalovirus (HCMV) genotypes. However, little is known about the genotype populations acquired during primary HCMV infection.The aim of this study was to assess the HCMV genotype populations present in the blood of non-immunocompromised patients experiencing primary HCMV infection.HCMV glycoprotein B (gB), glycoprotein H (gH), and UL10 genotyping was performed on HCMV-positive serum samples of 36 immunocompetent patients during primary infection by sensitive gB- and gH-genotype-specific real-time-PCR assays and by UL10 sequencing.In all cases only one gB-gH-UL10 genotype was detected. In contrast, mixed-genotype infections were found in 4 of 14 immunocompetent patients experiencing HCMV reactivation/reinfection (P=0.004).Thus, the data support the presumption that multiple HCMV genotypes in immunocompetent individuals are often a result of serial reinfection rather than primary coinfection with different strains.