In this work, a 40 GHz mm-wave balanced band-pass filter (BPF) is realized using coupled structure consisting of symmetric feed lines and stepped-impedance resonators (SIRs). For differential-mode operation, the BPF circuit exhibits band-pass characteristic; for common-mode operation it behaves as a band-stop unit. The designed balanced BPF circuit is realized by using TSMC 0.35-μm standard process. Good agreement was observed between simulated and measured results. The measured passband center frequency is at 38.8 GHz, with a minimum differential-mode insertion loss of 5.87 dB and a 3-dB bandwidth of 9.6 GHz.