In vitro inoculum production of arbuscular mycorrhizal (AM) fungi has several advantages over traditional systems. In particular, it allows an important production of contaminant-free fungal propagules in a short time, and it is more economical. Therefore, our goal is to develop in vitro inoculum production of AM fungi of interest. This goal has been achieved with a Glomus sp. originating from Symbiom, Czech Republic. Until now, the molecular characterization on mitochondrial and nuclear DNA has not permitted to distinguish this isolate from Glomus irregulare (Syn. Rhizophagus irregularis; DAOM197198). However, the Glomus sp. isolate presents morphological (white drop-shape spores) and physiological (faster growth) characteristics different from those of DAOM197198, and new molecular approach should be developed to distinguish it.