The aim of this study was to produce pyrolysis oils from waste high impact polystyrene (HIPS) and acrylonitrile-butadiene-styrene (ABS) in a pyrolysis plant equipped with a fluidized bed reactor. The influence of various reaction parameters, such as temperature, feed rate and the kind of fluidizing medium, was investigated. The maximum oil yields were about 87 wt.% (474 degrees C) for the HIPS and 84 wt% (525 degrees C) for the ABS. A higher feed rate and the use of product gas as a fluidizing medium were favorable for the oil production. The oils produced from the HIPS pyrolysis consisted chiefly of toluene, ethylbenzene, styrene, cumene, cl-methylstyrene and styrene dimers and they appeared to be usable directly as a fuel or chemical source. Main compounds of the ABS pyrolysis oils were similar to those obtained from the HIPS, except for nitrogen-containing compounds. In the nitrogen mass balance of the ABS pyrolysis products, most of the nitrogen was concentrated in the oil with a content of 6.5-7.1 wt.%. The pyrolysis oil from the ABS seemed to require further treatment for its use as a fuel source. (C) 2013 Elsevier B.V. All rights reserved.