Virtual instrumentation merges sensing technologies with hardware and software technologies to create flexible and sophisticated instruments for various control and monitoring applications. Biomedical applications require sophisticated and flexible instrumentation, accomplished by using general-purpose computing platforms with various application-specific input/output devices. Virtual instrumentation brings many advantages over "conventional" instrumentation. Employing general-purpose computing platforms significantly decreases the price of instruments. Standard system interfaces allow seamless integration of virtual instruments in a distributed system, whereas software reconfiguration facilitates flexibility and scalability. Most general virtual instrumentation concepts are directly applicable in biomedical applications; however, specific features of the biomedical instrumentation must be taken into account. In this article, we present a brief history and current state of virtual instrumentation for biomedical applications. We explain the general architecture of a virtual instrument, describe the most frequently used tools and platforms, and present typical examples of biomedical applications of virtual instrumentation.