The investigation of length–weight relations and condition factors of prawns in River Ethiope, is a necessary pre-condition to their successful farming, exploitation and management in the system. The present study captured a total of 241 prawns from three designated study stations; Aghalopke (1), Ovwori (2) and Sapele (3). The prawns were separated into three species: Macrobrachium dux, M. macrobrachia and Macrobrachium. spp. Female prawns constituted 50.60 % of the prawn community with length and weight intervals of 4.1-11.1cm and 0.14-20.5g respectively, 15.77% were male; 3.1-10.1cm long, and weighed 0.15-14.62g, while 28.63% were juveniles with length and weight of 2.2-3.5cm and 0.09-1.18g respectively. The tie-up attributes intervals: a (intercept) and b (slope) varied from 0.88-5.12 and 0.43-3.29 respectively, displayed positive allometric growth except Macrobrachium spp in station 1. Lengths and weights of the prawns showed no correlation with the physico-chemical parameters which were notably variable. The empirical demonstration of the interauxesis equation and the condition factor forecast good prawn yield, if the system is brought under proper control and management.