The use of lithium-drifted germanium detectors for fast-neutron flux measurement has been investigated. The proposed detection mechanism is observation of the internal conversion electrons emitted during the de-excitation of the 691 KeV 0 + state in 72Ge following excitation via fast-neutron scattering. A 4.0 cm 3 (approx.) planar Ge(Li) detector has been calibrated for neutron flux measurements over the energy range E n = 700−5000 keV. The absolute efficiency for this detector (ratio of neutrons detected to neutrons incident on the detector) has been determined to be (8.2±0.5) × 10 −4 at E n = 1500 keV which is about 10% of the full-energy peak efficiency for 1332 keV 60Co gamma rays. Cross-sections for excitation of the 691 keV 0 + state in 72Ge via neutron scattering have been extracted from the measured efficiency function. These cross-sections can be used to calculate efficiency functions for other detectors. Insensitivity to thermal neutrons, gamma-ray discrimination capability and stability are among the desirable features of this type of fast-neutron detector. Submicrosecond timing is not possible because of the isomeric nature of the 691 keV 0 + state in 72Ge. While Ge(Li) detectors suffer radiation damage from fast-neutron bombardment, the detector used for these measurements withstood an integrated dose exceeding 10 10 neutrons/cm 2 without serious deterioration of its performance.