Introduction: Dental caries is the most widely spread oral disease in the world, yet it tends to go untreated in underserved communities. The primary objective of the Atraumatic Restorative Treatment (ART) is to reduce the indication of tooth extraction by means of a low-cost technique. Objective: The aim of this study was to compare the clinical performance of two glass-ionomer based restorative materials:(Fuji IX GP) and (ChemFil Rock) high viscous glass-ionomer restorative materials (HVGIRMs), in treatment of proximal carious lesions using the atraumatic restorative treatment. Materials and Methods: A Total of Fifty-two participants of both genders (26 Females and 26 Males), with mean age range from (14-16) years, participate in a controlled clinical study in Egypt. Teeth were sub-divided in to two subgroups according to HVGIRMs used. For both genders, the first half of the cavities (n=13) was restored with Fuji IX GP HVGIRM. While the half was restored using ChemFil Rock HVGI (n=13). The restorations were applied by one operator. Digital photographs, direct and indirect clinical and radiographic examinations were made after completing the restorations, one week (baseline), three and six months for restoration's evaluation using ART criteria. Results: After six months, according to ART criteria, the survival rate of ChemFil Rock HVGIRM used in proximal restorations was not statistically significant different from that of Fuji IX GP HVGIRM. Gender predilection had no statistically significant effect on the survival rate of any tested restorative materials. Conclusion: ART is suitable for this study. Fuji IX GP and ChemFil Rock HVGIRMs had an acceptable clinical performance in restoring occluso-proximal ART prepared cavities of permenant teeth after six months of clinical service. Gender predilection had no effect on the clinical performance of occluso-proximal ART restorations