The objective of this project is to design a water bath temperature control with PID controller on microcom-puter based system. Implementation of a low cost tempera-ture sensors calibration by yourself. The paper details the cooling and heating based on peltier modules that controlled by peltier driver circuit. Circulate system bring to use a homo-geneity of the liquid temperature and this project has a protect system in case of peltier modules overload. RTD Pt-100 sensor is to measure the temperature in the bath. Control and display implemented in LabVIEW to control the other devices that all controlled by MPDAQ board which connected to USB port of microcomputer. Operating result on this project to control a temperature ranges from 10 °C to 80 °C. The least error 0.05 % and the best accurancy 99.95 % at 50 °C. The error 1.29 % and the least accurancy 98.71 % at 20 °C. Heating time from 25 °C to 75 °C is no less than 35 minutes and cooling time from 25 °C to 15 °C is no less than 12 minutes. Stability to 0.1 °C at 10 °C and stability to 1.05 °C at 70 °C. In experi-mental using a digital thermometer as reference that calibrate at Biomedical Instrument Calibration Unit, Siriraj hospital certificate No. DIT-451/55. In experimental result on this project to be useful in temperature sensors calibration.