  We present a study of $W^+W^+jj$ and $W^-W^-jj$ production including leptonic
decays in hadron-hadron collisions. The full electroweak and QCD induced
contributions and their interferences are calculated at leading order. We find
that, for inclusive cuts, the interference effects can be large if the jets are
produced with large transverse momentum where, however, the production rate is
suppressed. We also discuss the vector-boson-fusion (VBF) cuts and show the
validity of the VBF approximation. The NLO QCD corrections to the QCD-induced
channels are also calculated. Compared to the previous calculation, we allow
the intermediate $W$ bosons to be off-shell. For on-shell $W$ production, we
obtain an excellent agreement with previous results. Our code will be publicly
available as part of the parton level Monte Carlo program VBFNLO.
