AbstractTheoretical basis is presented for determining Poisson's ratio in uniaxial compression tests of cylindrical specimens. A simplified measurement technique and instrumentation for obtaining the required parameters are described in detail. Experimental data for Centennial sweet potato flesh at 72°F and four moisture contents are provided and analyzed to give the time dependent master curve and the time‐moisture shift factor; thus, the time and moisture influenced viscoelastic property of Poisson's ratio is completely specifi