We present our protein-protein interaction (PPI) network visualization system RobinViz (reliability-oriented bioinformatic networks visualization). Clustering the PPI network based on gene ontology (GO) annotations or biclustered gene expression data, providing a clustered visualization model based on a central/peripheral duality, computing layouts with algorithms specialized for interaction reliabilities represented as weights, completely automated data acquisition, processing are notable features of the system. RobinViz is a free, open-source software protected under GPL. It is written in C++ and Python, and consists of almost 30 000 lines of code, excluding the employed libraries. Source code, user manual and other Supplementary Material are available for download at http://code.google.com/p/robinviz/.