A preliminary study on spawning period, length at maturity, and main fishing grounds of Decapterus macrosoma (shortfin scad) collected from coastal waters of San Fernando, Romblon, Philippines were conducted. A total of 1,168 specimens were collected from July 2016 to December 2017. From these specimens, the minimum and maximum total lengths were 11.50 cm to 22 cm while its body weights ranged from 13 g to 100 g, respectively. D. macrosoma was capable of spawning whole year round. Two spawning peaks were observed (February and August to September) based on the monthly mean gonadosomatic indices. Male appeared to dominate female as evidenced by its sex ratios. The lengths at 50% maturity of female and male D. macrosoma were estimated at 15.29 cm and 17.22 cm, respectively. D. macrosoma was caught in volume through commercial ring net at a depth of about 150 m-200 m within the municipal waters. Coastal waters near barangay Canjalon and Agtiwa were identified as the main fishing grounds of D. macrosoma in San Fernando, Romblon. This initial data on spawning period may be used as a basis in implementing closed fishing season of D. macrosoma in the locality, and the length of maturity may as well be used for the allowable size of the capture of this species.