Luminescent properties of chemically cross-linked gels ofeuropium, terbium, and neodymiumsalts of poly(methacrylic acid) swollen in methanol wereinvestigated by steady state and time-resolvedfluorescence. The obtained results demonstrate the aggregation ofrare earth metal ions bound to thenetwork with the formation of multiplets. The energy transferEu3+ → Nd3+ in the gel showsthatmultiplets consist of three to four rare earth metal ions (togetherwith the gel countercharges). This isone of the first observations of multiplet formation in ion-containingpolymer gels.