This work reports the magnetic phase transition in the polycrystalline La_0.90Pr_0.10Mn_0.8Co_0.2O₃ perovskite sample. The solid-state reaction was used for the synthesis of the polycrystalline sample. The detailed study of this polycrystalline sample includes the structural characterization by Rietveld refinement. The surface morphology by FESEM demonstrates a well-prepared sample. The EDAX spectra show the elemental confirmation in the prepared sample. For the detailed magnetic study, M–T and M–H measurements were performed by applying various external magnetic fields at various temperatures. The ZFC and FC curves have been measured under variable temperatures and they show the magnetic phase transition from ferromagnetic to paramagnetic. Also, the splitting between ZFC and FC curves depicts the relaxation mechanism in the sample. The scaling law suggests the orientation, strain effects, and domain structures. The FWHM of the peaks of both (ZFC & FC mode) is increasing with the applied field. This may be due to the magnetic relaxation in the sample. The M–H loops also confirm the ferromagnetic to a paramagnetism phase transition; however, the non-saturating appearance of M–H curves of all three systems is indicative of high magnetic anisotropy.