A magnetic labelling technique has been used to examine particle residence time distributions in a continuous spouted bed. For a single particle species, the nearly perfect mixing observed found by others is confirmed. For a binary particle system, perfect mixing of each component is found, but the mean residence times are not equal. The ratio of mean residence times is found to be dependent on the fountain height and bed depth; the influence of some of the underlying physical mechanisms in the fountain, free surface and outlet regions can be seen.