A simple self-tuner algorithm based on the tuning of the proportional band of a conventional Proportional Integral mode action is proposed. The algorithm, based on intuitive reasoning as adopted by process experts is simpler than many of its type specially from the viewpoint of implementation on a 8 or 16-bit microprocessor. It has been tested in a stable second order process model as also in an actual second order thermal process. Test results show that the proposed algorithm has an edge over its conventional discrete counterpart even when the latter is perfectly tuned.