Particle density plays an important role in the design and operation of thermoconversion reactors fed with bed of particles such as softwood bark (SB). Little information is available on the single particle density of SB and charcoal derived. As SB and softwood char (SC) particles are highly irregular in shape and size, conventional methods of particle density measurement cannot be applied. A method known as the water soaking and kerosene immersion procedure, used for density measurement of sugarcane bagasse, has been tested and adapted to the density measurement of individual particles of softwood (SW), SB and SC. The particle density has been determined to be 360, 482 and 299 kg m(-3) for SW, SB and SC, respectively. The average particle density of a typical SB feedstock sample comprised of ca. 30% SW and 70% SB was calculated to be 438 kg m(-3). (C) 2002 Elsevier Science Ltd. All rights reserved.