The most common forms of biomass available in Sri Lanka are fuel wood. Among fuel woods Hevea brasiliensis (rubber) play major role as firewood to fulfill energy requirements. Especially industries demanded by rubber are not enough to meet the demand of fire wood. In this context, traditional users of fuelwood face difficulties in maintaining a stable supply of fuelwood. Therefore, there is an essential need in identifying possible, potential and high efficient biomass energy source to fulfill energy requirement in the country according to country's energy policy targets.This study was designed to evaluate energy and mechanical properties of Nataw (Xylopia parviflora) to see its applicability as fuel wood in biomass boilers. To study the fuel wood characteristics of Nataw (Xylopia parviflora), individuals were categorized in to three diameter classes dbh class (5cm -15cm, 15cm -25cm ,25cm -35cm). In each individual four samples were taken from a wood disk extracted at breast height (1.3m). Moisture content, density, specific gravity, ash content, volatile matter, fixed carbon and biomass/ash ratio were measured from five individuals from each diameter class. Certain characteristics including moisture content, density, specific gravity, and ash content had no significant difference among three dbh classes. Volatile matter content was significantly higher and fixed carbon content was significantly lower than the other two types of dbh classes in 25cm -35cm diameter class, the largest diameter class. When compare energy characteristics of Xylopia parviflora with Hevea brasiliensis, moisture content (31.22%) ash content (1.24%) were lower than the rubber. However Calorific values (18.92 kJ/g) and FVI (3055) higher than the rubber concluding Xylopia parviflora could perform better than rubber as a fuel wood in biomass boilers.