The effect of heating rate on the thermally stimulated luminescence (TSL) emission due to the temperature lag (TLA) between the TSL material and the heating element has been investigated using Li2B4O7:Cu,Ag,P dosimetric materials. The TLA becomes significant when the material is heated at high heating rates. TSL glow curves of Li2B4O7:Cu,Ag,P material showed two main peaks after beta-irradiation. The kinetic parameters, namely activation energy (E) and frequency factor (s) associated with the high temperature main peak of Li2B4O7:Cu,Ag,P were determined using the method of various heating rates (VHR), in which heating rates from 1 to 40 K s(-1) were used. It is assumed that non-ideal heat transfer between the heater and the material may cause significant inconsistency of kinetic parameter values obtained with different methods. The effect of TLA on kinetic parameters of the dosimeter was examined.