This paper highlights the development of a new ensemble correlation, multiphase flow PIV technique. The particular approach discussed in this paper is a straightforward extension of single-phase PIV and one of the major advantages of the technique is that it employs a single CCD camera. This velocimeter measures the motion of the liquid phase and the bubbles using an ensemble correlation procedure of successive recordings of bubble-tracer patterns. Moreover, the ensemble correlation technique enables the simultaneous measurement of the concentration of tracer particles and bubbles. The performance of the PIV technique is studied using synthetic bubble-tracer patterns. The performance is gauged in terms of the amplitude of the displacement correlation peak pertaining to the bubbles and in terms of the valid detection probability of that same peak. Finally, the newly developed PIV technique is tested by studying experimentally the two-phase flow in a pseudo-two-dimensional bubble column.