The length-weight relationship (LWR) and condition factor of Schilbe mystus from Asejire and Oyan Lakes were investigated. The b-values, 3.3845 and 3.2402 for the relationship of body weight to body length for this species in Oyan and Asejire Lakes respectively indicated that it exhibited positive allometric growth. Comparison of the LWR of the specimens revealed that growth rate differs between the sexes, size groups and locations (p< 0.01). Out of the 4 size groups (with 5 cm interval) used for comparison of growth rates in the species, the largest size group (24.6-29.5 cm) had lowest condition factor. The mean condition factors of the fish in both lakes were above average.