We present a tool that facilitates the comprehension and re-engineering of complex multi-language program integrations (i.e. programs written using multiple programming languages and integrated in a single system). To this end, we classify and formalize program components and their relationships (known as program dependencies) used by different programming languages. Then, a specialized fool called PolyCARE (Poly-paradigmatic Computer-Aided Re-engineering) is introduced which automates the process of detecting and visualizing such dependencies. During the implementation of a prototype version of PolyCARE, it is observed that the combination of the unique characteristics of each individual programming language and paradigm can increase the complexity of program comprehension and re-engineering. For instance, integrating programs written using an object-oriented language that supports inheritance and polymorphism (e.g. C/sup ++/) and a functional language (e.g. Lisp) which uses a recursive style can have a significant impact on program comprehension. Finally, some early experiences from using PolyCARE indicate that its presentation model, transformation mechanisms and partitioning techniques constitute a promising platform for the re-engineering and maintenance of complex integrations of programs.