In the present paper the Young's modulus and adhesion coefficient of amorphous Ni-P coatings obtained from aqueous solutions were determined. The measurements were carried out using a vibrating reed apparatus. In the temperature range 550-590 K, crystallization of Ni and formation of nickel phosphide Ni3P were observed. The Young's modulus of Ni-P amorphous layers on stainless steel at room temperature was found to be about 112 GPa. The adhesion coefficient gamma of the examined layers depends on the layer thickness a (f) and strongly decreases for a(f) > 8 mu m. This dependence corresponds to the change of the relative adhesion coefficient of about 40% for 8 mu m < a (f) < 15 mu m. It was also shown that the adhesion coefficient does not depend on the temperature, at least in the range 300-550 K.