In this paper, a novel, inexpensive and reliable stair climbing wheelchair mechanism is proposed. Large variation in inclination angle of a traditional wheelchair while moving on steps posses high risk to the rider's safety. A new active Slider-crank mechanism is used to minimize any variation in inclination angle of the wheelchair during climbing up or down on stairs. This, in-turn, reduces the risk of wheelchair toppling on steps. Kinematic model of the proposed wheelchair is developed and MATLAB simulations are performed to inspect the behavior of wheelchair on stairs. In addition, the mechanism is designed in such a way that the rider can sit towards the motion direction, which adds additional safety to the rider. It is envisaged that the novel step climbing wheelchair will enhance the mobility of the elderly people significantly.