The aim of this work was to analyze the effects of injection pressure and exhaust gas recirculation (EGR) on combustion, performance, and emissions characteristics of diesel premixed charge compression ignition (PCCI) mode. In this work, the injection pressure of diesel was varied from 500 bar to 1000 bar. The optimum injection pressure in diesel PCCI mode was identified based on the engine performance and emissions. The thermal efficiency was improved and smoke emission was drastically reduced as increasing injection pressure. However, injection pressure was not significantly influence the amount of NO, HC and CO emissions. The diesel PCCI mode was possible until a brake mean effective pressure (BMEP) of 2 bar since there was a vigorous knocking at higher BMEPs. Addition of EGR retarded the combustion process, suppressed the knocking, increased the thermal efficiency and extended the operating range to higher BMEPs of 3 and 4 bar.