Aluminum samples, together with sets of 12 flux monitor foils having different reaction thresholds, were irradiated in 6 different deuteron/beryllium neutron fields (Ed = 17.5 to 30 MeV). The shapes of the neutron spectra were determined by spectrum unfolding, using the known excitation functions of the monitor nuclides and their measured activities. In a second calculational step, the excitation function for the f(n, t)+(n, tn)] process on 27Al was obtained from the neutron flux distributions and the measured tritium activities. At both calculational stages the iterative code SAND-II and the generalized least-squares unfolding code were applied, the latter yielding additionally the error covariance matrix. The excitation function thus obtained has a maximum cross-section value of ∼8 mb at 25.5 MeV and compares well with the values obtained using monoenergetic neutrons in the region of 14 to 19 MeV.