Macrobenthos were performed the main group of the Caspian Sea funa while they have not completely
attentived espacilly in estuaries environoments. In this survey were studied eghiteen river estuaries in Guilan
province off Caspian Sea southwest. The macroinvertebrate sampling was conducted seasonally at egith
station during winter 2009 to summer 2009. The macrobenthos organisms were sorted and identified as
possible level in genus or species. The results presented fifteen orders including thirty six families. The most
presentation of genus belongs to Chironomidae family with twenty six genus while others were included
forthy three genus. The Stenogammarus genus had the normally distribution between seasons while the
most abundance was linked to Eukifferiella and Cricotopus during winter and spring 2009 nearly same as
Streblospio and Limnodrilus. The Cerastoderma was showed a high percentage with decresing of others
especially during summer 2009. In this paper have been described the fluctuation of benthic aboundance
according to biological characteristic and the environoment degradation.