High computational and throughput requirements in modern ultrasound machines have restricted their internal design to algorithm-specific hardware with limited programmability. Adding new ultrasound imaging applications or extending and improving machine's internal algorithms can require costly hardware redesigns and replacements of boards or of the entire machine. In an effort to address these problems, we have designed a high-performance programmable ultrasound processing subsystem, the programmable ultrasound image processor (PUIP), to fit within an existing ultrasound machine and support native ultrasound image processing. To utilize the PUIP's computing power and programmability, we have developed several ultrasound image processing applications. Multiple TMS320C80 processors were used to provide the PUIP with a computing power of 4 billion operations per second. Flexibility was achieved by making our system programmable and multimodal, e.g., gray scale, color flow, cine and Doppler data can be processed. To achieve real-time or near real-time performance, each new application to developed on the PUIP was broken down into its component algorithms. Each component algorithm was carefully researched to maximize its use of the multiple processors within the PUIP and each TMS320C80's ability to perform multiple operations in a single cycle. The PUIP enables many real-time ultrasound imaging applications within an ultrasound machine. It provides a platform for rapid testing of new concepts in ultrasound processing and allows software upgrades for future technologies. The PUIP is a significant step in the evolution of ultrasound machines towards more flexible and generalized systems bridging the gap between many innovative ideas and their clinical use in ultrasound machines.