Spectrophotometric Intracutaneous Analysis (SIA) is a fast, non-invasive and completely safe method of pigmented skin lesions differentiation with distinct advantages over clinical and dermatoscopic diagnosis of melanoma. It is easy to perform and allows to examine the skin lesions with great accuracy and in a highly objective manner. The sensitivity of the method reaches the value of 96%. It has also been shown that SIAscopy is the most reliable and reproducible of melanoma non-invasive diagnostic techniques. The device, termed SIAscope operates by emission of harmless radiation ranging from 400 to 950 nm into the skin and next, by a measurement of the reflected light quantity for each wavelengths. It is possible because individual components of the skin vary in their optical properties. They absorb and/or reflect light to a various degree and interact preferentially with particular wavelengths of light. From the spectral measurements SIAscope extracts information regarding location, quantity and distribution of melanin, collagen and haemoglobin (i.e. vascularity) within the layers of the skin. The data are then displayed on the screen as the SIAgraphs, which are graphical representations of digital information. It has been established that melanoma displays a characteristic SIAscopic image. It allows doctors to diagnose the tumor early enough even without much experience.