  The negative dimensional integration method (NDIM) is a technique where
several difficulties concerning loop integration can be overcome. From usual
covariant gauges to complicated Coulomb gauge integrals, and even the trickiest
light-cone integrals one can apply the methodology of NDIM. In this work we
show how to construct a general formula -- we mean arbitrary exponents of
propagators, off-shell external momenta and distinct massive propagators -- for
one-loop scalar integrals, for {\it covariant} gauges, and apply it to one
through six-point loop integrals. We present detailed analysis of pentagon and
hexagon scalar integrals for massive/massless internal particles being external
momenta on or off mass shell.
