Both AmAlO3 and PuAlO3 perovskites have been synthesized and characterized using powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and Al-27 magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR). AmAlO3 perovskite showed a rhombohedral configuration (space group R (3) over barc) in agreement with previous studies. The effect of americium alpha-decay on this material has been followed by XRD and Al-27 MAS NMR analyses. In a first step, a progressive increase in the level of disorder in the crystalline phase was detected, associated with a significant crystallographic swelling of the material. In a second step, the crystalline AmAlO3 perovskite was progressively converted into amorphous AmAlO3, with a total amorphization occurring after 8 months and 2 x 10(18) alpha-decays/g. For the first time, PuAlO3 perovskite was synthesized with an orthorhombic configuration (space group Imma), showing an interesting parallel to CeAlO3 and PrAlO3 lanthanide analogues. High-temperature XRD was performed and showed a Imma -> R (3) over barc phase transition occurring between 473 and 573 K. The thermal behavior of R (3) over barc PuAlO3 was followed from 573 to 1273 K, and extrapolation of the data suggests that cubic plutonium perovskite should become stable at around 1850 K (R (3) over barc -> Pm (3) over barm transition).