Decomposition and insect colonization of pig (Sus scrofa L.) carcasses were observed over a 42-day period inside and outside a house in a suburban region of Edmonton, Alberta. Three freshly killed pig carcasses were placed outdoors on grass and three carcasses were placed in separate rooms inside a house in a suburban residential area. The carcasses were examined and sampled regularly. Outside carcasses were colonized rapidly by Calliphora vicina (R-D), Lucilia sericata (Meigen), Lucilia illustris (Meigen), Eucalliphora latifrons (Hough), Cynomya cadaverina (R-D), Phormia regina (Meigen), and Protophormia terraenovae (R-D). There was a delay of 5 days before inside carcasses were first colonized but all species except E. latifrons and L. illustris readily colonized at this time. Many more insects colonized the outside carcasses, and these were rapidly skeletonized. Inside, much fewer insects were present and decomposition was slowed and colonization extended. Dispersal patterns of postfeeding larvae inside the house on hard substrate were greatly expanded compared with those from carcasses on grass.