[en] Two series of complexes of meconic acid (H₃Mec) with rare-earths have been prepared by varying the preparative procedure. The compounds have the general formulae, [Ln(Mec) (H₂O)₂].3 H₂O (where Ln = La, Ce, Pr, Nd, Sm, Ho and Y) and [Ln(HMec) (H₂Mec) (H₂O)₂].4 H₂O (where Ln = La, Pr, Nd and Sm). The infrared spectral data indicate that the carboxylate groups are bound to the rare-earth metal in a bidentate fashion. Thermal studies indicate that two water molecules are coordinated in each case. The complexes are probably polymeric. (author)