Software design patterns are documented best practice solutions that can be applied to recurring problems. The information about used patterns and their placement in the system can be crucial when trying to add a new feature without degradation of its internal quality. In this paper a new method for recognition of given patterns in object-oriented software is presented. It is based on static and semidynamic analysis of intermediate code, which is precised by the run-time analysis. It utilizes own XML based language for the pattern description and the graph theory based approach for the final search. The proof of concept is provided by the tool searching for the patterns in .Net framework intermediate language and presenting the results using common UML-like diagrams, text and tree views.