In the present study, the effects of gasoline-diesel fuel blends (GDFBs) on the combustion, engine performance parameters, and NOx emission have been investigated in a Ford XLD 418 T type turbocharged pre-chamber automobile diesel engine. Experiments have been performed for (2, 4, 6, 8 and 10) % (by vol) gasoline ratios at different engine speeds for 1/1 fuel delivery rate. It is found that ignition delay and heat release rate increase with increasing gasoline ratios. Also, engine performance parameters and NOx emission are improved by using GDFBs and improvement tendency becomes more obvious at moderate speeds. For example; brake specific fuel consumption and fuel cost decrease approximately 2.97 %, 5.29 % and 4.11 % and 1.70 %, 4.04 % and 2.86 % for all of the gasoline ratios at (2000, 2500 and 3000) rpms, respectively. Effective power increases at the levels of 1.20 %, 2.01 % and 1.92 % and NOx emission decreases approximately 10.04 %, 10.33 % ve 15.21 % for all of the gasoline ratios at (2000, 2500 and 3000) rpms, respectively. As a result, combustion, engine performance parameters and NOx emission of this engine have been improved by using (2-10) % GDFBs.