The effect of LPG fuel with different Propane to Butane volume ratio compositions on the performance of dual fuel engine under variable operational and geometrical conditions are investigated. Different LPG Composition of 100:0, 70:30, 55:45, 25:75 and 0:100 are used in this study. All measurements are carried out using a single cylinder, naturally aspirated, four strokes, indirect injected, water cooled modified Ricardo E6 engine. The data indicates that different LPG fuel composition has minimal effect on the engine efficiency and has strong impact on the levels of generated combustion noise. The pure Propane or Butane performs relatively lower than a mixture of both gaseous fuels. (C) 2012 Elsevier Ltd. All rights reserved.