SUMMARY
Loxosceles rufescens, commonly known as the Mediterranean Recluse or Mediterranean Fiddle-Back Spider is recorded from Iran for the first time. The genus Loxosceles contains 103 accepted species, two of them (including L. rufescens) are cosmopolitan. All Loxosceles species tested so far possess necrotic venoms, which is a unique characteristic among the Order Araneae. Considering this characteristic, it is of medical importance to determine a specific geographical distribution of these spiders. Collecting methods include visual inspection and direct hand collecting. All of the specimens were collected in Tehran.Six specimens of both sexes were collected from parks, houses and apartments. The characteristics of the genus, which are the unique arrangement of six eyes in three diads, the violin shaped mark on the cephalothorax, and the short tibia of adult male palpi with narrow base and it’s embolus which is about as long as the width of the globular bulb were observed and recorded. Having the cytotoxicity of the venom and its urban distribution in mind, L. rufescens is probably among the more important spider species of Iran. Since there are no reports of loxoscelism from Iran, we assume that the bites are either infrequent or misdiagnosed. Therefore further studies are needed to clarify the medical importance degree of this species.