In this investigation we report on superconducting properties ofinsituformed multifilamentary Cu‐Nb3Sn composites produced by a powder‐metallurgical technique. The wires contain 10 wt% Nb in Cu–1 wt% Sn and consist of discontinuous superconducting filaments embedded in a normal‐conducting matrix. They can carry resistanceless currents exceeding 105A/cm2(at zero field and 4.2 K). The critical current density depends strongly on the reduction of the cross section by wire drawing, the annealing temperature, and the tin content. The superconducting properties of these wires are uniform and insensitive to bending.