Gasification is one of the thermochemical conversion methods to produce both product gas and solid char. The quality of the product gas widely differs depending on the type of the gasification agent used in the gasification process. Therefore, one of the important parameters in the design phase of the gasification system is the gasification agent. In the present study, a laboratory scale bubbling fluidized bed gasifier was used to gasify the waste tire with the gasification agents of air&CO2, air&steam and steam. Within this frame, the effects of gasification agents, bed material particle size, CO2 to air ratio, steam to air ratio, steam temperature and steam to fuel ratio on the quality of the product gas were investigated. In order to determine the composition of the product gas, an online gas analyzer, which can measure CO, CO2, CH4, H-2 and O-2 components, was used. By using the measured gas compositions, the lower heating value (LHV) was calculated to represent the quality of the product gas. Comparing the gasification agents of air&CO2, air&steam and steam, the LHV of the product gas was obtained 9.59, 7.34 and 15.21 MJ/Nm(3), respectively. The repetition and uncertainty calculation of the tests were performed. (C) 2012 Elsevier B.V. All rights reserved.