The aim of this research is to determine the temporal changes of physico-chemical environmental parameters and chlorophyll concentrations in the Gediz River Deltaic Zone. For this purpose, water samples were taken from 11 stations monthly in 1998-1999. In this study, minimum and maximum concentrations of temperature, pH, dissolved oxygen and salinity are as follows; 9-34 0C, 7.28-8.68, 0-13.6 mg/l and 0.58-52.6 percent respectively. The results of the other measured environmental parameters were between 0.36-30.25 microg/l for chlorophyll, 0.00-90.06 microgat/l for N02**-N, 0.12-687.74 microgat/l for N03**-N, 0.02-370.5 microgat/l for NH4**+-N, 0.04-211.12 microgat/l for P04**3-P and 0.0-421.4 microgat/l for Si02-Si. Average values were 20.13 for temperature, 21.41 percent for salinity, 7.04 mg/l for dissolved oxygen. 7.26 for pH, 5.12 microg/l, for chlorophyll, 14.59 microgat/l for N02**-N, 130.51 microgat/l for N03**-N, 61.098 microgat/l for NH4**+-N, 13.61 microgat/l for P04**3-P and 102.91 microgat/l for Si02-Si.