Cu-Ni thin film strain gauges for diaphragm-type pressure sensors were developed. Thin films of Cu-Ni alloys of various compositions were deposited onto glass and stainless steel substrates by RF magnetron sputtering. The effects of composition substrate temperature Ar partial pressure and aging on the electrical properties of Cu-Ni film strain gauges in the thickness range 500~2000$AA$ are discussed. The maximum resistivity(95.6 $mu$$Omega$cm) is obtained from 53wt%Cu-47wt%Ni films while the temperature coefficient of resistance(TCR) becomes minimum(25.6ppm/$^{circ}C$). The gauge factor is about 1.9.