Mobile devices are becoming an inseparable part of our lives and personalized location-based mobile services are gaining more and more popularity. The scope of this paper is to illustrate the design choices, the implementation, and the testing, of a personalized mobile city transport advisory system (PECITAS), built for the citizens and city guests of Bolzano, Italy. Using PECITAS the user can obtain, directly on his mobile phone, recommendations for personalised paths between two arbitrary points in the city. The paths are illustrated by listing the various connections that the user must take to reach the destination using public transport means and walking. The recommendations are selected in a personalized way, using a knowledge-based recommendation technology, and for each user the suggestions are computed according to their travel-related preferences. The concepts of travel and user profiles are introduced in order to rank different routes in the city and provide the top ranked t...