—Cooperative communications leverages the spatial diversity available in a wireless network enabling multiple radio nodes work together to improve the overall system performance. When a destination receiver combines the signal from an originating source with the associated signals from relay nodes, significant improvements in the bit error rate performance can be achieved. This paper details the measured bit error rate performance of a three-node cooperative communication system operating in a software defined radio testbed. The measured performances of several types of cooperative physical layer protocols are compared to similar systems operating over a single wireless link. The measured results include cooperative systems operating with a maximum ratio combining technique and two cooperative coded systems using hard decision decoding.