The aluminum coordination state of the molecular sieve SAPO-37 has been studied by Al-27 multiple quantum (MQ) magic angle spinning (MAS) NMR spectroscopy. Although the 1D Al-27 MAS NMR spectra of the aluminum sites show complex patterns, the 2D 3Q MAS NMR spectra of SAPO-37 samples, submitted to different treatments, lead to the detection of four distinct framework Al species in the as-synthesized sample, i.e., (i) tetrahedral Al sites with four phosphorus atoms, (ii) tetrahedral Al sites with one (or more) Si as nearest neighbors interacting with tetrapropylammonium (TPA), and Al coordinated with (iii) tetramethylammonium (TMA) or (iv) water. Also, the Al environments with or without Si neighbors are distinguished for the first time in calcined, template-free H-SAPO-37. By use of H-1 spin echo editing MAS NMR experiments, a new proton signal at 3.4 ppm is observed in the calcined H-SAPO-37. By H-1{Al-27} and H-1{P-31} spin echo double-resonance experiments, this new signal is assigned to a kind of framework Al-OH hydroxyls caused by partially broken Al-O bonds. These aluminum defect sites originate either from the attack by a residual small amount of water, generated during the burning out of templates at high temperature in SAPO-37, or from the initial stage of the dehydroxylation process during the calcination.