Introduction The resonant properties of mechanical resonators provide valuable parameters for liquids density and viscosity measurement. The viscosity of liquids in industry and medicine has always been of interest to researchers. Methods In this paper, a viscosity sensor is designed and fabricated for liquids based on mechanical resonator and electro- magnetic actuators. In this proposed sensor, a coil is used to monitor the output of this sensor. Results This sensor is proposed to measure the blood viscosity, while its results for some people blood viscosity is reported and verified. Conclusion The exact design of the proposed sensor and its experimental results are presented using a prototype for some liquids that indicate the sensor precision.