Four strains isolated in Iran from pulmonary specimens of unrelated patients are proposed as representative of a novel Mycobacterium species. Similarity, at the phenotypic level, with Mycobacterium kansasii is remarkable with the photochromogenic yellow pigmentation of the colonies being the salient feature. They differ, however, genotypically from this species and present unique sequences in 16S rRNA, hsp65 and rpoB genes. The average nucleotide identity and the genome-to-genome distance fully support the status of an independent species. The name proposed for this species is Mycobacterium persicum sp. nov. with AFPC-000227T (=DSM 104278T=CIP 111197T) as the type strain.