Assessment of length-weight relationship and condition factor of a commercially important mollusc species, Periwinkle, Tympanotonus fuscatus, from Okrika estuary was conducted from October, 2015 to February, 2016. A total of 120 samples of the species were hand-picked from the mangrove ecosystem of Okrika. The results obtained showed that the gastropod species had negative allometric growth patterns with a growth exponent, b value of 2.18. This value was confirmed as negative allometric, because it was significantly different (p<0.05) from 3 when a t-test was carried out. The mean condition factor, K of the species was 18.9, which indicated that they were in good condition during the sampling period. This study recommends that further research needs to be conducted because the sampling duration (4 months) might be too small to make a valid, rigid and concrete conclusion. Also efforts should be undertaken to reduce the pollution load in order to safe-guard this valuable resource for the local population.