The paper is a summary of already published results on the Aspect.NET project, our aspect-oriented programming toolkit for the .NET platform. The latest of our results up to now have been only discovered in Russian journals, so the primary goal of the paper is to widen the scope of publicizing our results. The paper overviews goals, key ideas and history of the Aspect.NET project and its use in our research on refactoring cloud applications for Microsoft Azure. The Enterprise Library Integration Pack for Microsoft Azure is a solution by Microsoft to separate cross-cutting concerns in developing cloud applications. Using this library implies modification of the target application’s source code. In practice, there appear situations when updating the sources is undesirable or impossible, since they can just be confidential. The paper presents a method of seamless integration of aspects and the target application using the Aspect.NET toolkit which allows the developers to avoid changing the source code of the tar