The present invention provides a process for producing pyridine bases which comprises reacting an aliphatic aldehyde and/or a ketone with ammonia in the presence of a catalyst in gaseous phase, said catalyst comprising a zeolite containing (a) an element belonging to the platinum group and (b) at least one element selected from the group consisting of the elements of Groups IIB, IIIA and IVA of the periodic table and the having an atomic ratio of Si to elements consisting of Al, B, Fe and/or Ga of about 12 to about 1,000 and a constraint indedx of about 0.8 to about 12.