A Perturbed Angular Correlation (PAC) study was performed on the La1−x CdxMnO33+δ system that presents a rich variety of structural and magnetic phase transitions as a function of the oxygen content (δ) or as a function of temperature (T). The PAC signal at room temperature allowed the determination of the Electrical Field Gradient (EFG) parameters and to correlate them with the lattice average symmetry namely the orthorhombic (O′ or O*) Pbnm and rhombohedral (R) R$$ \overline 3 $$C phases measured by X-ray diffraction.