  I describe a method to calculate a class of three-loop selfenergy diagrams
for arbitrary internal masses and external momentum. This method combines
analytical results and numerical integration, and is suitable for
implementation in a computer program to produce fast and accurate results. For
the class of Feynman diagrams considered in this paper this method leads to a
two-fold integral which needs to be evaluated numerically. Results are given
for a range of masses and external momentum.
