An investigation of short-packet communications (SPCs) of a single hop system where there is a presence of co-channel interference at destination. The average block error rate (BLER) of the destination is derived in accurate as well as asymptotic closed-form expressions. The affects of some parameters like: the number of interference sources, the transmit power of the interference source on the system performance and the number of channel uses at the destination are considered. The results of the theory are evaluated by Monte Carlo simulation.