Frequency hopping is a technique that wireless devices communicate in a way that the transmission frequencies are alternated in a pre-determined ordered hopping pattern known only to the sending and receiving devices. In this paper, we develop an algorithm called Frequency Hopping Pattern Detection to detect the frequency hopping pattern of a wireless ad hoc network. The algorithm is performed in three stages. Stage 1 locates the first frequency in the pattern; stage 2 detects the remaining frequencies; and stage 3 calculates the entire hopping pattern. All three stages work together and guarantee the capture of all frequencies used, the pattern in which they occur, and the length of transmission for each frequency. The algorithm is simulated in a VHDL environment. Simulation results verify the correctness of the algorithm. Key words – frequency hopping, wireless networks, spread spectrum, pattern detection