Manganites DyM3IMg3Mn4O12 and DyM3IBa3Mn4O12 (MI = Li, Na, K) were synthesized by the solid-state reaction of dysprosium and manganese(III) oxides and magnesium and corresponding alkali metal carbonates. The X-ray powder diffraction studies showed that the crystals are orthozhombic with the following unit cell parameters and densities: DyLi3Mg3Mn4O12—a = 10.88 A, b = 10.73 A, c = 19.63 A, V0 = 1656.2 A3, Z = 8, ρcalc = 5.36 g/cm3, ρpycn = 5.11 ± 0.05 g/cm3; DyNaMg3Mn4O12—a = 10.55 A, b = 10.72 A, c = 18.28 A, V0 = 2067.4 A3, Z = 8, ρcalc = 4.60 g/cm3, ρpycn = 4.88 ± 0.09 g/cm3; DyK3Mg3Mn4O12—a = 10.56 A, b = 10.72 A, c = 20.89 A, V0 = 2206.0 A3, Z = 8, ρcalc = 4.60 g/cm3, ρpycn = 4.92 ± 0.06 g/cm3; DyLi3Ba3Mn4O12—a = 10.53 A, b = 10.69 A, c = 21.28 A, V0 = 2395.4 A3, Z = 8, ρcalc = 5.58 g/cm3, ρpycn = 5.98 ± 0.12 g/cm3; DyNa3Ba3Mn4O12—a = 10.53 A, b = 10.74 A, c = 23.00 A, V0 = 2602.3 A3, Z = 8, ρcalc = 5.39 g/cm3, ρpycn = 5.30 ± 0.07 g/cm3; DyK3Ba3Mn4O12—a = 10.52 A, b = 10.75 A, c = 25.69 A, V0 = 2905.2 A3, Z = 8, ρcalc = 5.04 g/cm3, ρpycn = 5.00 ± 0.18 g/cm3.