The invention is directed to a method of synthesising silicoaluminophosphate and aluminophosphate molecular sieves using synthesis templates that contain at least one template of general formula R.sup.1R.sup.2N--R.sup.3, wherein R.sup.1 and R.sup.2 are independently selected from the group consisting of alkyl groups having from 1 to 3 carbon atoms and hydroxyalkyl groups having from 1 to 3 carbon atoms; R.sup.3 is selected from the group consisting of 4- to 8-membered cycloalkyl groups, optionally substituted by 1 to 3 alkyl groups having from 1 to 3 carbon atoms, and 4- to 8-membered heterocyclic groups having from 1 to 3 heteroatoms, said heterocyclic groups being optionally substituted by 1 to 3 alkyl groups having from 1 to 3 carbon atoms and the heteroatoms in said heterocyclic groups being selected from the group consisting of O, N, and S. In particular, the present invention relates to the synthesis of silicoaluminophosphate molecular sieves of the CHA framework type having a low silicon to aluminium atomic ratio.