Identification of aquatic macrophytes and determination of water quality parameters of the   River Benue and its floodplain in Makurdi was carried out from February to July 2008. Three study sites were selected:  Abattoir floodplain as Site 1, Part of River Benue as Site 2 and the Floodplain at Wurukum as Site 3. Water was sampled and analyzed to determine Physico-chemical parameters and nutrient levels. Three main aquatic macrophytes were also identified namely Eichhornia crassipes, Ipomoea aquatic and Nymphae lotus, and were analyzed to determine their levels of minerals and metal concentration. These levels were found to differ significantly (P<0.05) with sites and macrophyte species The temperature ranged between 20.0 – 23.60C.with the mean value of 21.8±1.08. The highest temperature was recorded between March and April. Dissolved oxygen ranged between 3.6-4.9mg/l and there was no significant difference in the three sites but the highest value was recorded in June 2008. Secchi disc visibility recorded ranged from 0.5-1.9meters. The lowest depth was found in Site 3 (0.5m) and the highest in Site 2(1.9m). pH range of 5.9-6.8 was recorded within the period of study. The highest pH mean value of 6.54±0.21 was recorded in site 1. Phosphate concentration recorded ranged from 0.07-0.20mg/l and the level found in site 1 differed significantly with  the one in site 2. The concentration of nitrate ranged from 1.0-2.10mg/l but showed decrease from February to July as the water become diluted with rain water. The concentration of the minerals and metals found in the macrophytes were present. The potassium found in Nymphae lotus in Site 3was significantly higher than that found in Eichhornia crassipes in site 1. While Iron found in Eicchornia crassipes in site 1 was markedly higher than that found in Nymphae lotus in site3. In both cases, the concentration of both metals in site 2 was moderate.