Idle emissions of unburnt hydrocarbon (HC), CO, CO2, NOx, particulate matter (PM) and noise were measured from multi cylinder direct injection diesel-fueled engine. The purpose was to evaluate the hazards collateral to operate the engine at idle speed for long periods of time. Experiments were conducted at various speeds (900, 1000, 1200 and 1500 RPM) and for a 20 min period of time. The measurements were taken each 5 min. The results indicate that increasing idle time increased CO, HC, NOx, PM and noise, in the same time reduced CO2 concentration. Increasing idle time deteriorated combustion causing lower CO2 while the other emissions increased highly. Increasing idle speed improved the combustion and reduced CO, HC, PM and noise while increasing CO2 and NOx. Increasing engine speed enhanced combustion resulting in higher CO2 concentration, but it also increases combustion temperatures which resulted in higher NOx.