The blotchfin dragonet Callionymus filamentosus Valenciennes, 1837 is a Red Sea immigrant that was first recorded from the Turkish coast in 1994. To date, there has been little or no information on the biological parameters of C. filamentosus in the Mediterranean Sea. The present study aims to first determine the age and growth parameters of blotchfin dragonet C. filamentosus established in the Iskenderun Bay, northeastern Mediterranean. A total of 341 C. filamentosus were caught by commercial vessels from Iskenderun Bay (northeastern Mediterraenan, Turkey) between October 2012 and September 2013. The maximum age was found to be 5+ years for both sexes combined, the 1+ age group comprised of 56.0% of samples. The total length distribution of C. filamentosus ranged from 7.2-17.5 cm, and the weight distribution from 3.24-41.89 g. Growth equations for females were calculated as W=0.0131xL(2.820) (R-2 = 0.985) for males as W = 0.0155xL(2.757) (R-2 = 0.989) and for all individuals as W=0.0142xL(2.792) (R-2 = 0.987). Von Bertalonffy growth parameters were L-infinity = 21.22 cm, K= 0.235 year(-1), t(0) = -2.101 years for females, L-infinity = 22.24 cm, K = 0.215 year(-1), t(0) = -2.182 years for males, and as L-infinity = 21.93 cm, K = 0.213 year(-1), t(0) = -2.150 years for combined sexes. Overall total mortality was estimated as 0.62 year(-1), natural mortality was 0.41 year(-1) and fishing mortality was 0.21 year(-1).