Absorbencies of different DNA samples were studied using the well known photopyroelectric (PPE) technique and Fourier Transform Infrared (FTIR) spectrometer. In the fi rst method, wideband radiation absorbance from an infrared (IR) pulsed wideband source (PWBS) by DNA samples were detected and compared with FTIR spectrum. It was shown that the PPE technique results are useful and comparable to FTIR in distinguishing different DNA samples of biological interests