QCLs on computer chips just got one step closer to reality. We have just demonstrated room temperature lasing of a quantum cascade laser grown on a lattice-mismatched substrate. An InP based design was grown on a GaAs substrate, utilizing a buffer layer between the InP and GaAs. If similar techniques can be used to grow the GaAs layer on a Si substrate, then QCLs can be grown on Si wafers, allowing the integration of QCLs on computer circuits.