The paper considers the formalization of the stages and modeling of the mammographic examination procedure in the design of medical computer decision support systems. The mammographic examination process is presented in a generalized model, which consists of functional, structural, and mathematical models. The functional model (context diagram) is made using the functional modeling methodology. When analyzing the context diagram, four main functional blocks were identified: register a patient; perform registration and analysis of mammograms; carry out diagnostics; form a survey protocol. If there are standards for maintaining medical records and drawing up examination protocols, the first and last blocks are easily automated. The article focuses on the second and third blocks. At the mammogram analysis stage, the sub-stages “Perform preliminary processing” and “Perform morphological analysis” are essential. Preprocessing of mammograms (adaptive filtering, changing brightness or increasing contrast, etc.) is carried out using digital image processing methods to improve visualization quality. The result of morphological analysis is selecting structural elements and forming a set of diagnostic signs in the form of parameters of the found structural elements. Because some elements of mammograms (microcalcifications) have an irregular structure, specialized morphological analysis methods are used, based on taking into account the features of the images under consideration and their transformation methods in the form of the useful signal, in particular, fractal dimension models. The developed formalized models made it possible to reasonably design the decision support system’s structure during mammographic examinations, information, mathematical, software, and hardware to increase medical services’ efficiency and minimize the risks of medical errors.