Abstract: We will study the behaviour of canonical height functions associated to rational functions on totally p-adic fields. For each prime p, including  p
, we will classify all rational functions 
 such that there is a positive constant 
 with the property that the associated canonical height 
 on the maximal totally p-adic field admits only finitely many values less than 
. This might be seen as a dynamical version of results of Schinzel and Bombieri and Zannier.