The international Anzali Lagoon has a significant role as a settlement at the southern part of Caspian Sea to purge the entrance of sewage water and conserve the aquatic resources and many fresh water rivers entered to it. The aims of this study was the determination of temporal and spatial variability of Chlorophyll a, nutrients and water physicochemical parameters in the 15 rivers at the utmost Anzali lagoon. The stations were selected at the nearest place of the rivers reaches to Anzali Lagoon. The sampling were done monthly from June 2012 to June 2013. The results shows that annual means (±SD) were, Chl.a 3/17±2/73µgl/L ,water depth 0.93m ,water temperature17.13^oC ,secchi disk transparency 19/6±3/79cm, DO 7/39±0/53 mg/L , pH 7/82±0/27 , TP 0/25±0/19 mgl/L , TN 1/61±0/45 mg/L ,BOD₅8.16±1.88,Fe 1.56±.13 mg/L and Mn 11.94±0.07 mg/L. The highest levels of nutrients were in the rainy seasons; on the contrary the highest level of Chlorophyll a was in summer and winter. The results showed that entering nutrients to Anzali Lagoon was in high amount and it was depended on temperature and precipitation.