Surface water harbors several useful aquatic plants. Eichhornia crassipes is an invasive plant found in several aquatic ecosystems in the Niger Delta including rivers, creeks and creeklets. This study investigated the physicochemical and proximate composition of Eichhornia crassipes from River Nun, Amassoma axis, Nigeria. Standard analytical methods were employed for both water quality and proximate analysis. Results showed that the physicochemical properties ranged from 6.910 – 7.350 (pH), 25ºC (temperature), 0.000 – 0.017 mg/l (salinity), 10.333 – 34.333mg/l (total dissolved solid), 25.700 – 40.533 NTU (turbidity), 0.903 - 3.333 mg/l (total hardness), 3.4333 – 5.466 mg/l (total suspended solid), 33.167 – 68.000 µS/cm (conductivity), 0.500 – 3.466 mg/l (chloride), 0.566 – 0.866 mg/l (sulphate), 0.117 – 0.394 mg/l (nitrate), 0.800 – 2.333mg/l (calcium), 0.333 – 0.816mg/l (potassium), 0.533 – 1.310mg/l (sodium), 0.390 – 1.466 mg/l (magnesium), 0.023 – 0.463 mg/l (iron) and 0.003 – 0.023 mg/l (manganese). Proximate composition including moisture content, ash, protein, lipid, fiber and dry matter ranged from 82.733 – 87.760%, 6.216 – 7.700%, 3.656 -5.036%, 1.836 -3.023%, 5.700 – 7.166% and 12.283 -17.300% respectively. Analysis of variance showed that there were significant variations (P<0.05) in all the parameters across the sample batches.  The proximate composition of Eichhornia crassipes from River Nun provide vital information that indicates that the plant could be used for the production of value added products such animal feeds and purification of water
