This data set contains directly determined complex Poisson's ratio from axial and transversal strain measurements. Here, the axial and transverse strains were measured locally with strain gauges (K-CXY3-0060-3-350-O, HBK, Darmstadt, Germany) on cylindric polymethyl methacrylate (PMMA, EH-Design, Wörrstadt, Germany) samples with a diameter of d = 30 mm. Dynamic mechanical analysis (DMA) was performed with the piezoelectric actuator (8P-035.20P, Physik Instrumente, Karlsruhe, Germany) driven by the high power amplifier (E-482, Physik Instrumente, Karlsruhe, Germany). Small strain amplitudes excitation in the frequency range from 0.1 Hz to 1000 Hz are performed. To ensure the oscillation around a strain amplitude, a static preload is applied by a universal testing machine (RM50, Schenk, Germany). Transversal and axial strain is then measured on the PMMA sample with strain gauges in compression mode. The material response in the time domain is transformed to the frequency domain using the Fast Fourier Transform. This gives the axial and transverse amplitude as well as the axial and transverse phase shift. With the variable from the frequency domain, the complex Poisson's ratio is calculated in post-processing. The data set contains the calculated complex Poisson's ratio of three measured PMMA samples.