Telepathology involves rendering diagnostic opinions on specimens at remote locations using computer and telecommunications technologies. Consultations are a routine practice pattern in pathology, as there is a large amount of diagnostic and prognostic information available from the examination of biopsy material that requires an extensive knowledge of diseases and their clinical implications. Pathologists therefore frequently request opinions from those who subspecialize in various diseases. The use of video technology to examine and consult on microscopical slides has been validated, although sparsely and with a number of technical issues as yet unresolved. There are two principal paradigms for telepathology: remote dynamic screening by robotic video microscopy and remote diagnosis from selected still video microscopical images. The former is more appealing to most pathologists; however, it requires very high speed telecommunications links that are expensive and may not be available in a given location. The latter method entails a significant reduction in the data on which the diagnosis is rendered, as one is dependent on the fields selected at the remote location. In addition, there are hybrid systems that combine limited robotic capabilities with high-resolution still images. Image compression can increase the number of images that can be transmitted over an otherwise-limiting telecommunications infrastructure. JPEG is the current standard for such compression. Despite certain limitations, telepathology has been demonstrated successfully at several sites around the world. As this technology matures, systems will offer higher resolution, standardization of file formats, and better compression at lower cost.