The literature related to the incorporation of transition metal ions (TMI) into aluminophosphate (AlPO) and silicoaluminophosphate (SAPO) molecular sieves is reviewed. Microporous crystalline metal aluminophosphates (MeAPOs) and metal silicoaluminophosphates (MeAPSOs) represent an important group of inorganic materials because of their high potential as adsorbents and catalysts. This review focuses mainly on the spectroscopic characterization of TMI containing MeAPOs and MeAPSOs covering the literature through 2000. The characterization of these materials is summarized and discussed in the light of possible isomorphous substitution of transition metal ions into the aluminophosphate framework. Moreover, the literature devoted to the use of these materials in catalysis and adsorption is reviewed.