A fluidized sand bed reactor was used to study the production of gases from polyethylene (HDPE) at five nominal temperatures (ranging from 500 to 900 degrees C). Both HDPE primary decomposition and wax cracking reactions take place inside the reactor. Yields of 13 pyrolysis products (methane, ethane, ethylene, propane, propylene, acetylene, butane, butylene, pentane, benzene, toluene, xylenes, and styrene) were analyzed as a function of the operating conditions. The results are compared with the data obtained by pyrolysis of HDPE in a Pyroprobe 1000, where secondary wax and tar cracking is small. Correlations between the products analyzed with those of methane are discussed.