Optical and structural properties of InGaN/GaN quantum wells having growth interruption were investigated using high-resolution x-ray diffraction, photoluminescence and transmission microscopy. InxGa1−xN/GaN (x>0.25) six pair quantum wells used in this study were grown on c- plane sapphire by metalorganic chemical vapor deposition. The growth interruption was carried out by closing the group-III metal organic sources before and after growth of InGaN quantum well layers. With increasing the interruption time, the quantum dot-like region and well thickness decreases due to indium re-evaporation or thermal etching effect. As a result, PL peak position is blue-shifted and intensity is reduced. The size and number of V-defect did not vary with interruption time. The interruption time is not directly related with formation of the defect. The V-defect in quantum wells originates at threading dislocations and inversion domain boundaries due to higher misfit strain.