The Wankel rotary engine is a potential alternative to the reciprocating engine in hybrid applications because of its favorable energy to weight ratio. In this study, a Wankel rotary engine was modified to run on a hydrogen gasoline blend. Hydrogen enrichment improved the performance of a lean-burn spark-ignition rotary engine operating at high speed and wide open throttle conditions with the original ignition timing, using 0%, %2, 4%, 5%, 7%, and 10% hydrogen energy fractions at the intake. The experimental results showed that adding hydrogen to gasoline in the engine improved the thermal efficiency and the power output. Hydrocarbon and carbon monoxide emissions were reduced while nitrogen oxide emissions increased with the increase of hydrogen fraction. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.