This paper presents a practical implementation of a current-mode universal filter circuit using unity-gain cells, i.e., voltage and current followers. The presented universal filter uses four passive components and three unity-gain cells. Two grounded capacitors in the presented universal filter are appropriate for the integrated circuit manufacturing process. However, a resistive matching constraint is required for the high-pass filter, notch filter, and all-pass filter responses. 0.18 µm CMOS technology parameters and supply voltages of ± 1 V are used in the SPICE simulations. Several experimental studies verify the theory.