This article employs roll call vote data and Bayesian ideal point estimation to examine inter-party dynamics in the Argentine Chamber of Deputies between 1989 and 2007. It highlights the presence in the Argentine Congress of a strong government vs. opposition dimension as well as identifies the relative position on this dimension, vis-à-vis the governing party, of the most prominent non-governing parties. Special attention is paid to the evolution of inter-party legislative dynamics during Argentina’s brief experience with coalition government (1999-2001) and to party behavior in the Chamber during the final two years of President Néstor Kirchner’s term in office (2005-07)