Butanol-acetone (BA) mixture is considered a green energy resource because it releases fewer emissions than other fuels. BA can produce via fermentation from biomass (agricultural waste and residues) that is non-edible. The benefits of butanol have been supported by many studies as additive fuel for conventional diesel due to its exceptional fuel properties such as high burning velocity and heating value. However, the cost of butanol production is the main issue of using it as a fuel because of high recovery and production costs. It is cheaper to produce BA than butanol because it is not necessary to separate the butanol from other chemicals in the biofuel. Many researchers have investigated the fermentation process to produce a fuel mixture of acetone-butanol-ethanol (ABE) with a 3: 6:1 ratio. However, a number of studies demonstrate the drawbacks of using ethanol as an additive for diesel engines because of unsuitable properties for diesel engine such as lower heating value, cetane number and corrosion behaviour so BA with no ethanol is a better additive for diesel than ABE. This paper investigates the effect of using a butanol/acetone (BA)-diesel blend on exhaust gas emissions and engine performance. The test was performed for different blend ratios of BA to diesel (10BA90D, 20BA80D and 30BA70D) at engine speeds of 1400, 2000 2600 RPM in a single-cylinder diesel engine. This study has shown that brake power (BP) is maximum at 10% BA at all engine speed, approximately 5% higher than D100. The brake thermal efficiency (BTE) of 10% BA was comparable with D100 at all engine speeds, but was slightly increased by 6% and 8% at all engine speeds when the BA ratio was 20% and 30% respectively. CO emission levels have a significant decrease for all BA blend with a maximum 64% reduction than D100; CO2 emission was correlated with BP; NOx decreased at all BA blend with a maximum 10% reduction than D100; and the exhaust gas temperature decreased for all BA blend by 15.6% compared to D100. BA is shown to be a good renewable fuel additive to diesel because it can improve energy efficiency and reduce pollutant emissions.