A bi-monthly comparative study of heavy-metal accumulation (Pb, Zn, Fe, Cu, Mn and Cd) in water hyacinth (Eichhornia crassipes), water and sediment was done for a period of 12 months in Ologe lagoon, Lagos State; between June 2007 and May 2008. Six sampling stations were studied using standard techniques. The study was undertaken to assess the level of Phytoremediation by water hyacinth in the study area. Data obtained were analyzed using the descriptive and correlation coefficient matrix. The ranges, means and standard deviation of some physico-chemical factors measured were: water temperature. 27.1 - 28.5°C (27.7+0.5); pH, 6.1 - 7.6 (7.0+0.5); conductivity, 104.7 — 207.01.S/cm (163.5+36.5); TDS, 52.3 — 104.0mg.11 (82.4+18.1); DO, 6.2 - 7.2mg/I (6.7+0.4); salinity, 0.02 — 0.04°1„ (0.02+0.01); TSS, 6.8 -21.01-twill (13.8+4.6); Total Hardness.. 67.3 — 109.2mga (91.7+17.2); and Cl-, 12.5 — 30.0mga (21.0+7.2): respectively. The correlation coefficients showed that positive correlation occurred between metals in water and sediments: (r = 0.891). And mostly negative between metals in plant and the environment (r = -0.893). Metals accumulated in plant showed higher concentrations than that found in the water, but highest in the sediment. Evidently, water hyacinth acts as bio-accumulator with the ability to hyper-accumulate heavy metals from the water body through its root system.