A direct boundary element method (BEM) was recently proposed for inductance extraction. Though faster than other volume integral methods, it still suffers from as many as 7N unknowns where N is the number of panels. A mixed BEM for inductance extraction is proposed in this paper, which combines indirect boundary integral equations (BIEs) of double layer potentials within conductors and direct BIEs within dielectric (between conductors). With this mixed BEM, the number of unknowns is remarkably cut down from 7N to 4N, and correspondingly, the CPU time spent on solving the linear system decreases greatly. Two interconnect structures are simulated to demonstrate the validity of this method.