European energetic safety is belongs to the most discussed economic issues. This paper analyses impact of sudden, large-scale and persistent gas supply disruptions on the economy. This situation has been observed in real economy, more particularly in Central Europe and Balkan countries during Russia-Ukraine gas crisis at January 2009, where the gas supply was cut-off for 13 days. We will analyse the effects of this cut on Slovak economy, which belongs to one of the most affected. Economic analysis will be based on Computed General Equilibrium methodology – CGE model. Our aim is to estimate gas failure as an exogenous non-marginal supply shock with serious impact on aggregated and structural economic indicators. First quick estimation about possible daily losses at level about one third of daily GDP was confirmed. As a result of this disruption, there was implemented project in Slovakia to allow full reverse flow at main pipeline from Czech Republic. Slovakia can be now supplied from the west in case of unpredictable situation.