The paper reports the synthesis of Ba1−xSrxTiO3 (BST) for x = 0.20, 0.25, and 0.30 via hydroxide co-precipitation route to result into the BST nanoparticles of size nearly 50 nm. The La0.67Sr0.33MnO3 (LSMO) is also synthesized using co-precipitation route to achieve nanocrystaline particles. Further, the magnetodielectric (MD) composites of BST0.20, BST0.25, and BST0.30 are formed by addition of the LSMO at y = 0.1 and 0.2. The parent BST compositions are analysed for its dielectric properties. The composite LSMO-BST (LBST) is investigated for the variation of dielectric constant and impedance spectra as a function of applied magnetic field for the frequency between 500 Hz to 1 MHz. The observations on MD effect show that the dielectric constant possesses contributions due to magnetic field dependant interfacial polarization and variations due to the induced stress.