In this study, the effect of injection timing and compression ratio on performance, combustion and emission characteristics of a 4-stroke variable compression ratio (VCR) direct injection diesel engine is investigated for different compression ratios (CR) (14,16,18) and injection timings (IT) (21°, 23°, 25° before top dead centre (BTDC)) for mango seed oil methyl ester (MSME) biodiesel blend B20. The brake thermal efficiency (BTHE) is higher (28.86 %) and brake specific fuel consumption (BSFC) is lower (0.3 kg/kWh) at CR18 and IT 21° BTDC. Exhaust gas temperature (EGT) increases with brake power (BP) and showing lower value at higher CR and also at lower IT. The peak cylinder pressure attains at higher CR and advanced injection timing (25° BTDC). Net heat release rate is increasing with decreasing CR. At full load conditions, emissions of carbon monoxide (CO) ,carbon dioxide (CO 2 ) and hydro carbons (HC) are lower at lower IT and higher CR whereas nitrogen oxides (NO x ) is increasing with CR at all injection timings. The overall good performance and emission results show for CR18 and IT 21° BTDC.