In this paper, we design and implement a low-cost automatic neonatal incubator equipped with a baby weight monitor in order to remedy the difficulties encountered with the maintenance of incubators in developing countries. Indeed, severe temperature fluctuations inside an incubator can lead to neonate heat loss, hypothermia and apnoea, which are closely related to temperature and air flow. The implemented device has been developed by interconnecting three modules. The first is the acquisition module that senses the temperature and humidity, the second is the control module in charge of monitoring and controlling the operation of the system and the third is the human machine interface module through which a user can set operating parameters of the system. The mathematical modeling of Proportional-Integral-Derivative (PID) controller and heat transfer allowed the minimization of heat loss across the wall of the enclosure. The incubator has been tested and the target temperature of 37 °C was reached after almost 15 min. Results from numerical simulation performed with the same condition of the test showed a good agreement between the simulation results and experimental results.