Length-weight relationships (LWRs), condition factor (K), and relative condition factor (Kn) were estimated for 505 individuals. The species were: Awaous guamensis, Taenioides cirratus, Mysus gulio, Polynemus paradiseus, and Lates calcarifer from the Meghna River Estuary of southern Bangladesh collected between July 2018 and June 2019 by using traditional fishing gear (e.g. Dragnet, Purse net, Fixed Purse Net and Gill net). Total length (TL) was measured to 0.1 cm, and whole-body weight (BW) was taken to the nearest 0.1 g for each individual. The results of the length-weight relationship showed that the allometric coefficient, b values ranged from b= 1.48 (Lates calcarifer) to b= 3.28 (Awaous guamensis). The results revealed that Awaous guamensis showed positive allometry, whereas the other studied species showed negative allometric growth.  In this study, the mean values of the relative condition factor (Kn) were recorded as close to 1.0, thus the condition of the Meghna River Estuary was good for the growth of those five marine species. Hence, the present study proved to assist the management of those five endangered species in the Meghna River Estuary ecosystem.