This paper explores the business cycle in Bulgaria and the Baltic countries: Estonia, Latvia and Lithuania during the 1993-2005 period. The paper aims at deepening the understanding of the nature of output fluctuations. The neoclassical approach will be employed, much in the spirit of the Real Business Cycle (RBC) literature, which gives a general equilibrium picture of the transition process. The model used in this paper follows the methodology of King, Plosser and Rebelo (1988). Calibration parameters, taken from data on Bulgarian and Baltic economies, are used in the estimation procedure. Both the model and data series show that the major drop in output was due to productivity. In addition, the timing of the banking reforms coincides with the improvement of economic performance. This is a strong indication that banking regulations in place were crucial for the output performance throughout the period in Bulgaria and the Baltic countries, a finding that has important implications for economic policy.