This study was designed to study the length-weight relationship (LWR) and condition factor of the puffer fish, Lagocephalus sceleratus (GMELIN, 1789), an emerging fishery resource around Tobruk coast, eastern Libyan Mediterranean Sea. 181 fish specimens were caught by hooks and trolling lines during June 2021 from four artisanal fishery sites around Tobruk City, east of Libya namely: Main port of Tobruk, Al Tamimi, Al Agaila, and Kambut. The collected fishes were classified into juveniles and adults two groups. The total length (L) of fish was measured to the nearest 0.1 cm and total weight (W) was recorded to the nearest 0.1 g. Length-weight relationship and condition factors were investigated. Data were analyzed and power regression values were estimated by Statistical Package for Social Science (SPSS) program. The study showed that the averages total length of juveniles, adults, and all fishes were 26.13±3.60, 58.33±5.53, and 54.77±11.45 cm respectively, while the corresponding values of total weight were 159.02±74.22, 2243.79±703.18 and 2013.43±932.56 g. LWR indicated isometric growth for juveniles (W=0.008L^3.006), slightly negative allometric for adults (W=0.020L^2.856), and positive allometric for all fishes (W=0.004L^3.268). The Fulton´s condition factor (K_F) and relative condition factor (K_n) were found to be 0.84±0.08 and 1.03±0.10 for juveniles, 1.11±0.19 and 0.99±0.17 for adults, 1.08±0.20 and 0.93±0.16 for all fishes. These investigated parameters are essential pre-requisites for the assessment and management of puffer fish as invader fish.