New results are reported on the propagation of a vortex ring through immiscible fluid interfaces in the limit of high Weber number in microgravity and in I-G. The main objective of the tests is to detennine the effect of density and viscosity ratios on the dynamics of the interaction. It is shown that density ratio plays a controlling role in determining the outcome of the interaction. For small density ratio, i.e. a gas/liquid interface, the vortex ring forms a long column before the interface breaks. In contrast, for a density ratio of order one, i.e. liquids of matched density, the vortex ring propagates through the interface ‘and forms a drop. The effect of viscosity ratio for density ratio of order one is to change the size and structure of the liquid column during drop fonnation and the number (and location of satellite droplets formed. These results suggest that density ratio efkcts are more important than previously recognized in computational and experimental studies of multiphase flows.