We developed a new electronic stucture method, called pDME-PDFT, based on density matrix embedding theory and multiconfiguration pair-density functional theory, able to treat extended systems with periodic boundary conditions. Initial applications on oxygen vacancies in magnesium oxide showed that produces results that are comparable to the more expensive non-embedded MC-PDFT method. We then used pDME-PDFT to study larger models, namely the Mg 36 O 36 and Mg 54 O 54 surfaces, which are impractical to investigate with non-embedded MC-PDFT. Finally, pDME-PDFT gives results comparable with the more expensive and in many cases non-affordable NEVPT2-DMET method. We envision that pDME-PDFT will be used to investigate the electronic properties of defects in materials, as well as reactions on surfaces involving multireference systems.