In this paper, a bandpass filter realized on a flexible substrate made of a cellulose-based material is presented. The operating frequency band is selected in order to address industrial, scientific and medical (ISM) applications. The bandpass filter central frequency is equal to 2.45 GHz. The filter design exploits a quasilumped microstrip structure and the circuit realized from a copper adhesive laminate is shaped by laser. The bio-sourced material is a cellulose ester. The characterization of the proposed filter demonstrates that measurement and simulation data are in a very good agreement.