Since the prosperous wine industry in some seismic countries such as the US, Italy, New Zeeland, Chile and Argentina, among others, the seismic protection of wine storage tanks is of practical importance. Unanchored steel wine storage tanks may lift off their base due to the overturning moment caused by the hydrodynamic wall pressures generated during earthquakes. The partial uplift of the base can generate large inelastic rotation demands and possible failure at the shellbase connection. In this article, the seismic fragility of the shell-base connection of an unanchored steel wine storage tank is characterized. Moreover, an evaluation of external energy dissipation devices for an improvement in the seismic performance is presented. Fragility curves are calculated to evaluate the seismic performance. The fragility curves are developed by the results obtained from a mathematical model to perform the nonlinear time history analysis of a typical unanchored wine storage tank, with and without the external energy dissipation system, subjected to several artificial ground motions. The artificial ground motions are based on ground motion prediction from earthquakes recorded in Chile. Finally, the seismic fragility for the shell-base connection of unanchored steel wine storage tank located in Chile is presented. Furthermore, the seismic fragility of a same damage state for a typical unanchored steel wine storage tank with and without energy dissipation devices are compared. The limit state probability reduction is of 106%.