In the Netherlands, many cities aim to promote cycling as a solution for sustainable mobility. However, the bicycle parking shortage is common. The popularity of ‘car-free city’ concept provides the opportunity to solve the problem by replacing car parking spaces to bicycle parking spaces. This study used a GIS-based location-allocation method to optimally locate the bicycle parking facility in car parking spaces. Through a case study in the city centre of Leiden, the results show with the small amount of car parking spaces, bicycle parking shortage can be largely relieved.