The invention is directed to a method of stabilizing metalloaluminophosphate molecular sieves and catalysts derived therefrom. In particular, the invention is directed to a method of treating such molecular sieves with chemisorbed ammonia, which may be easily desorbed before or during use and after storage. The invention is also directed to formulating the molecular sieve into a catalyst useful in a process for producing olefin(s), preferably ethylene and/or propylene, from a feedstock, preferably an oxygenate containing feedstock.