With a recent energy crisis, alternative fuel, especially for transportation, has been explored. For particular fuel consumption distribution in Thailand, with twice diesel fuel consumption than gasoline, NGV and biodiesel have been successfully promoted to reduce this uneven diesel-gasoline consumption pattern; whereas, diesohol (10% ethanol blend in diesel) was tested for performance and emission with acceptable results. However, ethanol-diesel blend still faces challenges in finding suitable emulsifier, preventing water absorption from ambient and adapting existing distribution infrastructure to cope with low flash point. Hence, the present study evaluates feasibility in using butanol blending with diesel (BDx) due to no need for emulsifier, less water absorption and less difference of physical/chemical properties in the blends. Butanol and diesel were blended at butanol concentrations of 10, 20, 30 and 40% by volume (BD10, BD20, BD30 and BD40) without any emulsifier additive to observe solubility and stability. Relevant physical and chemical properties were measured and compared to specification of Thai diesel. Then, butanol-diesel blends of 5, 10, 15, 20, 25, 30, 35 and 40 by volume (BD5, BD10, BD15, BD20, BD25, BD30, BD35 and BD40) were tested with unmodified Isuzu commonrail engine (model 4JJ1) for engine performance, fuel consumption and emissions, with comparison to commercially available diesel in the market. The physical/chemical properties of the blends reveal acceptable values; whereas, the engine testing results reveal that BD15/20 can be used in commonrail engine without any modification to the engine since ECM (electronic control module) of the engine can maintain set lambda value despite the butanol blending. Nonetheless, higher than BD15/20 could deteriorate engine performance and fuel consumption.