This work describes the development of an electrochemical sensor for point-of-care measurement of zinc in blood serum. The sensor is based on the anodic stripping voltammetry (ASV) and consists of a three-electrode system including bismuth working electrode, an on-chip Ag/AgCl reference electrode, and a Au auxiliary electrode. The demonstrated sensor allowed rapid and accurate measurement of zinc in the physiological range (65~95 μg/dL). Thus, the developed lab-on-a-chip sensor permits measurement of Zn in blood serum with reduced sample volumes (200 μL from a drop of blood from a finger prick) and reduced turnaround time (10~20 min). Ultimately, this system will permit the quantification of Zn at the bedside of critically ill patients.