  We prove a limit theorem for the the maximal interpoint distance (also called
the diameter) for a sample of n i.i.d. points in the unit ball of dimension 2
or more. The exact form of the limit distribution and the required
normalisation are derived using assumptions on the tail of the interpoint
distance for two i.i.d. points. The results are specialised for the cases when
the points have spherical symmetric distributions, in particular, are uniformly
distributed in the whole ball and on its boundary.
