The quality of water from four coastal towns (Ayetoro, Idiogba, Bijimi and Asumogha) in Ilaje local government area of Ondo State was assessed using standard methods with the view of determining the level of pollution through anthropogenic activities and state of the aquatic ecosystem. The results of the analyses of the water samples showed that Dissolved Oxygen (DO) had the highest mean of 7.66 mg/l in Ayetoro while the lowest mean (7.53 mg/l) was recorded in Bijimi; Temperature had minimum

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... n value of 29.42 o C in both Bijimi and Idiogba and maximum mean of 29.75 o C recorded in Asumogha. The minimum mean of pH across the four locations was recorded in Asumogha (6.63) and the maximum mean was recorded in Idiogba (6.71). The conductivity of Idiogba had the least mean value of 41.00 μS/cm and Ayetoro had the highest mean value of 41.83 μS/cm. Salinity ranged from 16.35 o /oo in Asumogha to 16.65 o /oo in Idiogba and the minimum mean of hardness (84.57 mg/l) was recorded in Asumogha while the maximum mean of 87.16 mg/l was recorded in Ayetoro. Also, turbidity ranged between 41.95 NTU in Bijimi and 45.36 NTU in Asumogha. The result revealed that all the physico-chemical parameters of water determined (except turbidity and hardness) showed no significant difference across the four sampling stations at P<0.05. The result obtained is within the permissible level of aquatic biodiversity, set by United State Environmental Protection Agency and World Health Organization thus, the water can be classified as brackish and a good, stable and healthy aquatic ecosystem.