We analyze the circulation induced by cabbeling at the boundary between two stratified water masses of equal density but different temperature and salinity at any depth. Scale analysis of the dynamical equations shows that the isopycnals remain flat to a very good approximation, the result being that a simple expression for the vertical velocity can be obtained from the density equation. For parameters typical of a subsurface front in the slope water the estimated vertical velocity is about 1 m day -1. Larger speeds are possible in regions of small vertical density gradient, but we show that for the convergence associated with cabbeling to maintain a T-S front against diffusion typically requires a rather large temperature jump. Our analysis breaks down if the parent water masses are so weakly stratified that a mixture is heavier than the sources at any level. In this case an estimate of vertical circulation can be obtained by analogy with the thermal bar of dimictic lakes and the convection at a heated vertical wall. We also argue that the vertical density flux associated with double diffusion in the interleaving region of a T-S front should cause some net vertical motion, and we estimate 1 m day-1 for a particular front. While this value is small, it is not much less than a rough estimate of the vertical velocity associated with internal friction at a front across which a density jump occurs.