Agaricus subrufescens Peck is a cosmopolitan species of nutritional and medicinal interest. Three types of internal transcribed spacer (ITS) rDNA sequences were recently characterized for this species. Sequences of types A, B, or both types A and B are found in American and European specimens, while sequences of type C are found in Asian (China and Thailand) and Oceanian (Hawaii) specimens. We report on a collection of this species from Iran, for the first time. Both the morphological features and ITS sequence confirm its identification as A. subrufescens. Its ITS sequence was of type C and even identical to that of specimens previously reported from Hawaii, China, and Thailand. This sequence differed from those of Europe or the Americas, where most current cultivars originate. The discovery of a specimen likely native to Iran extends the known distribution range of the ITS sequence of type C from East Asia to Iran. More collections from West Asia (and elsewhere, for example Africa) would help to better know the distribution area of the different types of ITS sequences and to increase the available germplasm resources of A.subrufescens.