The application of MOSFET dosimeters in complicated mixed radiation fields for measurement of absorbed dose distribution in tissue equivalent phantoms has been studied. The spectra of secondary charged particles have been measured simultaneously with average absorbed doses by the same MOSFET dosimeter. A good correlation has been observed between neutron depth dose distribution in a water phantom obtained using MOSFETs in integral mode and a tissue equivalent (T. E. ) ionisation chamber. Such MOSFET dosimeters are a promising tool for micro-macro dosimetry in Boron Neutron Capture Therapy (BNCT) and Fast Neutron Therapy (FNT). Paired MOSFETs with one of the dosimeters covered by 10B have been applied for measuring of average boron dose distribution and microdosimetric spectra due to alpha particles and 7Li ions throughout a perspex phantom exposed in the epithermal neutron beam at the Brookhaven Medical Research Reactor (BMRR). © 1996 IEEE.