The orientation dependence of the piezoresistive effect of p-type single crystalline 3C-SiC thin film grown on a (100)Si wafer was characterized. The longitudinal, transverse gauge factors in [100] orientation, and longitudinal gauge factor in [110] orientation were found to be 5.8, 5.2, and 30.3, respectively. The fundamental piezoresistive coefficients p11, p12, and p44 of p-type 3C-SiC were obtained to be 1.5 10 11 Pa 1, 1.4 10 11 Pa 1, and 18.1 10 11 Pa 1, respectively. From these coefficients, the piezoresistive effect in any crystallographic orientation in p-type single crystalline 3C-SiC can be estimated, which is very valuable in designing micro-mechanical sensors.