The effects of feed rate of waste tires (0.21-0.52 kg/h), oxygen concentration (0- 11%), pyrolysis temperature (700-880 degrees C), and fluidizing gas velocity (1.5-3.0 u(mf)) on product (gas, oil, char) yield, composition, energy recovery, and heating value of the product gas have been determined in a fluidized-bed reactor (0.076 m i.d, x 1.2 m-high). The product yield, composition and heating value of the product-gas, and energy recovery are found to be independent of the feed rate of waste tires. The effects of oxygen concentration (0-6.5%) on the yield and production rate of product gas (H-2, CH4) are small but both decrease with oxygen concentrations above 6.5%. With increasing pyrolysis temperature, the gas yield and energy recovery increase, oil yield decreases, whereas the char yield remains constant. With increasing fluidizing gas velocity (u(o)), the heating value of the product gas increases linearly, the total gas-production rate decreases, but energy recovery remains almost constant.