The lyoluminescence (LL) technique using mannose, a monosaccharide, is described. Dose-response curves for ⁶⁰Co gamma -rays (5 rad to 120 krad), fission neutrons, 5.3 MeV and 15 MeV neutrons (100 rad to 20 krad) have been measured. After correction for the gamma contamination of the neutron beam the LL signal per rad in ICRU muscle tissue from the neutron irradiations has been derived and the relative effectiveness of the LL signal for fast neutrons in mannose has been calculated as 0.34+or-0.03 (fission neutrons), 0.63+or-0.07 (5.3 MeV neutrons) and 0.74+or-0.05 (15 MeV neutrons). These results are compared with the data from other systems. It is concluded that mannose can be used as a transfer system in neutron dosimetry, if its variation in sensitivity with neutron energy is taken into account.