Using extended X-ray absorption fine structure (EXAFS) spectroscopy, we have determined the solvation structures of various metal ions in non-aqueous solvents such as N,N-dimethylformamide, trimethyl phosphate, triethyl phosphate, tributyl phosphate, 1,1,3,3-tetramethylurea, acetonitrile, ethylenediamine, 1,3-propanediamine, and n- propylamine. In comparison with the hydration structures and the solvation structures in the other non-aqueous solvents reported so far, the characteristics of solvation structures are discussed on the basis of the size of the metal ion and the kind of donating atom of the solvent molecule. For oxygen-donating solvents, the solvation number of the first-row transition metal(II) ions decreases from 6 to 4 with increasing size of the solvent molecule. Since the decrease in the solvation number makes the steric crowdedness and the electrostatic repulsions around the metal center relax, the M (II)–O bond length in the oxygen-donating solvents is shortened with decreasing solvation number. In the case of nitrogen-donating solvents, the solvation number of the first-row transition metal(II) ions is usually 6, while the hybridization of the donating nitrogen atom affects the M–N bond length: M–N(sp³) > M–N(sp²) > M–N(sp). Furthermore, the difference in the M–N bond length is different from the metal(II) ion, which is interpreted by the degree of π back donation.