The design and fabrication of a tellurite based magneto-optical (MO) glass for MO fiber applications are presented and discussed. Two MO glasses based on the TeO 2 –PbO–B 2 O 3 –SiO 2 system were investigated in terms of thermal, optical and magnetic performances as a core/cladding pair for MO fiber fabrication. The optimal core and cladding elemental compositions were found to be: (58.8–60%) TeO 2 –(39.2–40%) PbO–(0.5–2%) B 2 O 3 mol% for core glass, and (76–58.2) TeO 2 –(36–38.8%) PbO–(0.5–2%) B 2 O 3 –(0.3–2%) SiO 2 mol% for cladding glass. The Verdet constant and Figure of merit of the fabricated glasses were measured under different wavelengths using a home-made optical bench.