In this checklist 528 spider species and subspecies belonging to 45 families and 230 genera that have been recorded from Iran are presented, of which, 43 records are considered as doubtful. Geographic distributions of all species are presented by main provincial areas of the country. Also, where necessary, we have provided comments on species distribution, species status or possible misidentifications. The list is dominated by members of the families Salticidae (98 species), Linyphiidae (69 species) and Lycosidae (63 species) with 18.7%, 13.1% and 12% of total species, respectively. The level of regional endemism and sub-endemism exceeds 15.5% and 5.6% of total species, respectively.