We describe the first case of tenosynovitis due to Mycobacterium heckeshornense, a mycobacterium characterized in 2000 and only incriminated in a few previous cases of infections. Molecular identification of this pathogen included 16S rRNA and hsp65 gene sequencing. M. heckeshornense may cause a wide spectrum of human infectious diseases and may be underestimated due to its phenotypic relatedness with Mycobacterium xenopi.