Objective: The aim of this study was to evaluate the effect of deproteinization procedure and different adhesive systems on treatment success of molar incisor hypomineralization (MIH) caused by inorganic content and mineralization deficiency in the enamel layer of the tooth in pediatric patients. Materials and Methods: One hundred and two patients who had moderate MIH and were between 7-10 years of age were selected among the patients who applied to our clinic and whose consent was obtained. In these patients, four groups (Group 1:NaOCl+Clearfil SE Bond+Filtek Z250; Group 2:Clearfil SE Bond+Filtek Z250; Group 3:NaOCl+Phosphoric Acid+Prime&Bond NT+Filtek Z250; Group 4:Phosphoric Acid+Prime&Bond NT+Filtek Z250) were created depending on the use of deproteinization agent and self-etch or total-etch adhesive system and restorations were performed. Deproteinization was provided by 5% NaOCl. The patients were evaluated clinically using the modified USPHS criteria. Data were analyzed statistically; p<0.05 was considered significant. Results: In restorations, at the end of 12 months; there was no failure in anatomical form, color match, surface roughness and postoperative sensitivity criteria. In terms of marginal adaptation and marginal discoloration, the highest success was observed in Group 3 (p<0.05). All restorations were found to be successful in Groups 1, 2 and 3 while 4 restorations were unsuccessful in Group 4 for secondary caries criteria (p>0.05). Group 3 with deproteinization and total-etch adhesive system was found to be the most successful group in the treatment of hypomineralized teeth (p<0.05). Conclusion: The combined use of deproteinization and acid application of total-etch adhesive systems increases the success in the treatment of MIH. More studies on the subject are needed.