Synthesis, crystal structures, and magnetic properties of melilite-type oxides A(2)MSi(2)O(7) (A = Sr, Eu; M = Mg, Mn) were investigated. These compounds crystallize in the melilite structure with space group P (4) over bar2(1)m. The Eu-151 Mossbauer measurements show that the Eu ions are in the divalent state. The Eu2MgSi2O7 is paramagnetic down to 1.8 K. Long-range antiferromagnetic ordering is observed at 3.4 K for Sr2MnSi2O7. On the other hand, the Eu2MnSi2O7 shows a ferrimagnetic transition at 10.7 K. From the magnetization and specific heat measurements, it is found that the Eu2+ (14 mu(B)) and Mn2+ (5 mu(B)) sublattices order antiferromagnetically. This result indicates that an interaction between f-d electrons (Eu-Mn) predominantly operate in this compound.