This work evaluates the feasibility of real-time wireless video streaming of medical ultrasound signals over 802.11g ad-hoc and 3G cellular broadband networks for disaster relief, rescue, and medical transport applications. Scalable H.264 encoded echocardiographic ultrasound image sequences were transmitted in real-time at specified image resolutions (VGA and QVGA) and frame rates (10, 15, 20, and 30 frames per second). Relevant transmission parameters such as data rate, packet loss, delay jitter, and latency were measured. The 802.11g network permits high frame rate, VGA resolution, has low latency and jitter, but is suitable only for short communication ranges, while the 3G cellular broadband network allows medium to low frame rate streaming at QVGA image resolution with medium latency. However, video streaming can take place from any location with 3G service to any other site with Internet connectivity. Physicians with expertise in medical ultrasound subsequently rated the diagnostic content of the transmitted videos relative to the original ultrasound video signals. The physicians observed that the image quality in the case of both 802.11g and 3G wireless transmission was fully to adequately preserved, while missed frames could momentarily decrease the diagnostic value. This research demonstrates that sufficient wireless bandwidth and efficient video compression make diagnostically valuable wireless streaming of ultrasound video feasible.