Macrobrachium is a freshwater prawn genus with a high economic value and habitability in Sulawesi, Indonesia. One of Macrobrachium that has not been described in many characteristics, is namely Macrobrachium mammillodactylus. This study aimed to determine morphometric and meristic variance, length-weight relationships, and condition factors of M. mammillodactylus from three rivers downstream of Rongkong watershed, South Sulawesi, Indonesia. A sampling of M. mammillodactylus was conducted from September 2018 to August 2019. The parameters observed were morphometrics, meristics, length-weight relationships, and condition factors.  The observed variables were total weight and total length to see growth patterns and condition factors, while 9 morphometric parameters and the number of serrations contained in the dorsal and ventral rostrum sections were conducted to see the discriminant of the observed variable characteristics. The coefficient values indicated female morphometric parameters were more heterogeneous than male. The population of M. mammillodactylus at Waelawi, Salujambu, and Pombakka Rivers obtained 2 groups, with the parameter morphometric and meristic not significantly different. The negative allometric growth pattern and condition factor (k) > 1, showed that the three rivers provide sufficient feed, low predator density, and moderate flow velocity. This study could be used for sustainable fisheries management and as primary data in conservation efforts of M. mammillodactylus at Rongkong watershed, South Sulawesi, Indonesia