Spontaneous ignition tests of various forest species were performed with a specifically designed apparatus. The forest species selected: Arbutus andrachne, Cistus incanus, Pinus brutia, Pinus halepensis, Cupressus sempervirens, Pistacia lentiscus, Abies cephalonica are very common in the Mediterranean region which is frequently devastated by forest fires. The same tests were performed in the presence of 20% (w/w) (NH4)(2)HPO4 (DAP) and 20% (W/W) (NH4)(2)SO4 (AS). The presence of DAP and AS prolonged the ignition delay time and this effect was more pronounced at low temperatures (i.e. <530degreesC). The autoignition delay properties of forest fuels treated with retardants were related to thermal analysis data obtained by thermogravimetry in nitrogen atmosphere. It was determined that the fire retardants shift the DTG major weight loss peaks of fuel to lower temperatures and increase the pyrolysis mass residue.