Provided are a neural network device for performing a neural network operation, a method of operating the neural network device, and an application processor including the neural network device. The neural network device includes a direct memory access (DMA) controller configured to receive floating-point data from a memory; a data converter configured to convert the floating-point data received through the DMA controller to integer-type data; and a processor configured to perform a neural network operation based on an integer operation by using the integer-type data provided from the data converter.