The lithium ion transference number (T-Li) and anion transference number (T-F) were determined for composite polymer electrolytes based on ethylene oxide (250 M-n) and hydrophobic fumed silica. These transference numbers were measured using electrophoretic nuclear magnetic resonance (ENMR), which essentially is a rapid Hittorf method. We demonstrated the validity and power of the ENMR technique by independently measuring both T+ and T- for a single sample and showed that T+ + T- = 1 (within experimental error). Measurement of T-F is typically easier and more accurate than measurement of T-Li. ENMR is a powerful technique for characterizing polymer electrolytes without the need for assumptions, such as treatment of the electrolyte as an ideal solution, or for multiple measurements and regressions, as required by methods based on concentrated solution theory.