Objectives: Analyze the succession of insects associated with the decomposition of bodies in two aquatic ecosystems in the Andean Amazon. Scope: Provide information on the insects associated with bodies that decompose within aquatic habitats and the duration times of each decomposition phase as a tool for the determination of the post-mortem submerged interval (PMSI). Methodology: Three carcasses were placed in a stream and three in a lake, the sampling carried out every five hours, from the moment of death to its skeletonization. Main results: Total decomposition lasted for 14 days in the stream and 16 days in the lake. Six decomposition stages were observed: submerged fresh, early floating, floating decay, bloated deterioration, floating remains and sunken remains. A total of 1172 organisms were collected on the carcasses in the stream and 1585 in the lake. Trophic relationships identified were: Shredders, collectors, predators, necrophages, sarcosaprophages and incidentals. In the stream, the caddisfly shredders were the most representative organisms in the submerged fresh stage. In the lake, the mayfly shredders, and hemipterous and odonate predators, were the most representative organisms in the early floating stage. The necrophagous and sarcosaprophagous diptera were the most representative organisms in the stages exposed to the surface in both ecosystems. Conclusions: The PMSI for both carcasses was similar in the two habitats, each showing six stages of decomposition, confirming that decomposition in lotic and lentic ecosystems is different from that observed for terrestrial environments.