Predicted scarcity of conventional fuels and their increasing cost have given rise to interest in alternative fuels like biofuels, ethyl alcohol, methyl alcohol, hydrogen, producer gas, acetylene etc. in order to meet the energy requirement. Gaseous fuels are good for clean burning, but are costly. In the present study, a single cylinder, four strokes, direct injection, vertical, water cooled, variable compression ratio, multi fuel engine was used to operate in dual fuel mode. In this experiment acetylene was inducted at a flow rate of 7 lpm at various compression ratios of 18:1, 18.5:1, 19:1 and 19.5:1. Results were evaluated and compared on the basis of combustion, performance and emission parameters. Peak cylinder pressure and brake thermal efficiency are found to increase whereas exhaust gas temperature decreases with increase in compression ratio. The brake thermal efficiency was found to be maximum (21.18%) at 19.5:1 compression ratio.