In this study, the effect of calcium treatment on the mechanical properties and fatigue behavior of low carbon steel material is investigated. By applying calcium treatment after aluminum deoxidation for steel cleanliness, the aim is to transform the inclusions into harmless structures and produce cleaner liquid steel. As a result of the study, calcium treated material’s tensile strength slightly increases while fatigue life decreases. SEM studies were conducted to evaluate the results and it was observed that while elongated inclusions were observed as well as spherical shapes in the untreated sample, the inclusions generally had a spherical shape in the calcium treated sample. After the steel cleanliness process, the mechanical properties of the samples were improved. The tensile strength of the calcium treated sample increased slightly. However, a significant decrease in fatigue strength was observed depending on brittle inclusions that occur as a result of the calcium treatment process.