Fatigue resistance of steel containing non-metallic inclusions (NMIs) varies widely, depending on many criteria; therefore, finding the most compromised types of NMIs is a sober objective that may significantly reduce severe damage and premature failure in many applications, such as bearings, gears, transmission shafts, etc. The Multiple Criteria Decision-Making (MCDM) methodologies have been used in this study to assess the more effective NMI types using the Analytical Hierarchy Process (AHP) by Expert Choice (EC) software. The five most common types of non-metallic inclusions selected are oxides, sulfides, carbides, silicates, and nitrides, based on different criteria: size, shape, distribution, mechanical properties, and quantity. The results showed that the oxide NMIs are the optimum type relative to the other four options regarding the fatigue resistance of about 35%, probably due to their spherical shape and small size. The most dominant criterion is mechanical properties, which have an effective percentage of 34.6% among the other criteria. It means that the reduction of other types rather than oxide NMIs probably enhances the fatigue resistance of the steel.