Length and weight data of fish populations are necessary in stock assessment models and ecosystem modelling. Also, they could be used to spatially compare between different fish populations under different environmental conditions. This study provides an updated information on the length weight relationships and condition factors of six fish species in Lake Nasser, Egypt. It also investigates how these parameters are affected by variation in environmental characteristics of the Lake, therefore it presents the first reference on the spatial and temporal variation of these data in Lake Nasser.