Electron magnetic resonance (EMR) spectra were measured on different La 1-xSr xMnO 3 manganites at the interval 100≤T≤420 K for studying an influence of the synthesis conditions on the magnetic homogeneity of the sample. The micron-sized crushed crystals La 0.833Sr 0.126MnO 3 and La 0.7Sr 0.3MnO 3 grown by fused-salt electrolysis and by floating zone melting with the Curie temperatures T C=320 K and 350 K, respectively, as well as nanosized sonochemically sintered powders La 0.7Sr 0.3MnO 3 (annealed, T C=340 K) were studied. The results obtained show that samples originated from bulk crystals are less homogeneous than the nanocrystalline one. Except for higher homogeneity, the nanosized sample demonstrates also a weaker magnetic anisotropy. As a result, strongly pronounced magnetic phase separation (revealed as coexisting ferromagnetic and paramagnetic signals in EMR spectra) is observed in crushed crystals.