The insects have important roles in this life, such as to determine the time of death or it’s usually called Post Mortem Interval (PMI). The study about this topic has not been reporting yet in Samarinda and it is a background to conduct this research, that aim to find out the kind of insects on wistar rat (Rattus norvegicus) carrions in Samarinda, East Kalimantan as a basic data for forensic entomology study. This study conducted using the observational method at 16 male wistar rats and 16 female wistar rats. All of the wistar rats were dislocated and wounded on the right abdomen 1 cm long. The observation was conducted 24 hours once. There were 4 wistar rat carrions (2 males and 2 females) observed every day to determine the decomposition stages and to collect the evidence (insect, eggs, larvae, and pupae). Every entomology evidence will be identified later. The result showed there were 4 decomposition stages, the fresh stage, the decay stage, the post decay stage, and the skeletonization stage. Based on that decomposition stages, there were 25 insects categorized by 15 families and 4 orders. The insect order that affected the decomposition stages most were Diptera and Coleoptera. Some of them were Chrysomya megacephala, C. albiceps, C. rufifacies, Staphylinus sp. and Platysomalocenti sp.