A novel Er complex C14H11ErN2O10●4(H2O) has been synthesized from a hydrothermal reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. Monoclinic, P21/c. a=14.0400(10) Å, b =11.2536(9) Å, c =12.9373(9) Å, α= 90°, β=102.010(6) °, γ=90°. V=1999.4 Å3. Z=8. R1 =0.0586, wR2 = 0.1684, T=293(2) K. The Er atom is nine-coordinated by two N atoms from two 2,6-pyridine dicarboxylic acid moleculars and seven O atoms. The molecular structure stabilized by the O-H…O hydrogen-bonding interactions.