Genital mycoplasmas are rare in extraintestinal specimens, but can cause disseminated infections in immunocompromised patients and wound infections after surgery or injury. We report two cases of Myoplasma hominis wound infections after lung lobectomy and kidney transplantation, and a case of M. salivarium wound infection after aortic graft replacement. Mycoplasmas grew in aerobic and anaerobic cultures as tiny colonies but were not observed by gram- or acid fast stain and were confirmed by MYCOFAST EvolutioN 2 kit or 16S rRNA sequencing. These cases indicated that mycoplasmas were probably underestimated in wound infections because they were not in suspicion. We suggest that Mycoplasma should be suspected when microorganisms are not readily observable in Gram stains but can be cultured. (Korean J Clin Microbiol 2010;13: 121-124)