Live mass was recorded for over 290 adult Odon. during peak flight season in Mississippi. Total live mass is reported for 19 spp., along with a quantitative species subset analysis of inter- and intraspecific sex partitioned mass. Fresh mass was significantly correlated with species and sex in Anisoptera (p = 0.021) and Zygoptera (p = 0.001), based on separate species-level analyses of the Libellulidae (n = 6 spp.) and Coenagrionidae (n = 4 spp.), respectively. Total live mass also was correlated with total body length in the libellulid dragonflies (r2 = 0.59-0.94, p<0.0001-0.03) and length-mass slopes were not significantly different among species. Limitations and cautions of mass prediction via proportionate size dimension(s) are discussed, some advantages of working with adults as opposed to larvae and measuring fresh mass as opposed to dry mass are described, and further study of length-mass relationships in adult Odon. is encouraged.