Gasoline direct injection (GDI) engines have picked up prominence in the current circumstances in light of lower fuel consumption and exhaust emissions. Mixture formation in these engines plays a critical role which affects the combustion, performance and emission characteristics. To get better mixture formation, various factors ought to be considered, of which intake port design is one of the factors of considerable importance. Therefore, in this study, a comparison of mixture formation, performance and emission characteristics has been analyzed in a GDI engine with conventional intake port and swirl intake port. The analysis is carried out on a four-stroke wall-guided GDI engine using the computational fluid dynamics (CFD) with the help of the CONVERGE. The validation of spray breakup model is carried out to the extent possible using the experimental results available in the literature. The analysis is carried out at four overall equivalence ratios at an engine speed of 2000 rpm., and a fuel injection pressure of 100 bar using a six-hole injector. From the results, it is found that better mixture stratification, higher indicated mean effective pressure (IMEP), and lower emissions are obtained for a GDI engine with the conventional intake ports at overall equivalence ratios (ER) of 0.5 and 0.6, whereas they are better in the engine with swirl intake ports at the overall ERs of 0.7 and 0.8. © 2019 SAE International. All Rights Reserved.