[en] A study was made on NaBH₄ solubility in aqueous-ammonia mixtures in NH₃ concentration range of 10-35 mass% at temperatures of 22, -5 and -9 deg C. Crystallization fields of nonsolvated sodium borohydride and its dihydrate NaBH₄ · 2H₂O were determined. Metastable region oversaturated solutions, coexisting either with NaBH₄ · 2H₂O, or with NaBH₄ · H₂O, depending on ammonia temperature and concentration was established in the system. Solubility of sodium borohydride in aqueous ammonnia increases with growth of temperature and ammonia content in the solution in the whole analyzed temperature and concentation range