Signal processing of Spectral Domain Optical Coherence Tomography Medical imaging techniques that are found in hospitals are X-ray imaging, MRI, ultrasound imaging, CT scan. Recently, a lot of scientific research work is being carried out with the aim of the improvement of these methods and the discovery of new non-invasive techniques. As a result, a new optical imaging technique, called Spectral Domain Optical Coherence Tomography (SD-OCT) was proposed in the early 2000s. Optical Coherence Tomography (OCT) is an emerging imaging technique having resolution in the μm range and depth of imaging in the mm range. In this paper we have described the basic principle, theory, types of OCT, signal processing steps and its applications in medical field. We have discussed some of the results related to signal processing that we got from simulation using MATLAB and Lab VIEW.