Summary. Consider a semimartingale of the form Yt = Y0 + t 0 asds + t 0 σs− dWs, where a is a locally bounded predictable process and σ (the "volatility") is an adapted right-continuous process with left limits and W is a Brownian motion. We consider the realised bipower variation processwhere r and s are nonnegative reals with r + s > 0. We prove that V (Y ; r, s) n t converges locally uniformly in time, in probability, to a limiting process V (Y ; r, s)t (the "bipower variation process"). If further σ is a possibly discontinuous semimartingale driven by a Brownian motion which may be correlated with W and by a Poisson random measure, we prove that √ n (V (Y ; r, s) n − V (Y ; r, s)) converges in law to a process which is the stochastic integral with respect to some other Brownian motion W , which is independent of the driving terms of Y and σ. We also provide a multivariate version of these results, and a version in which the absolute powers are replaced by smooth enough functions.