Four laboratory types of low molecular weight polybutadiene (PBD) with different 1,2-vinyl isomer contents were selected for microstructure characterization by nuclear magnetic resonance spectroscopy (NMR). By characterization of PBD's end groups, which is possible just in low molecular weight PBD, it was suggested which initiators and quenching reagents might had been used in PBD synthesis and how the polymeric chain was propagated. Also, the structure of adjacent parts of the polymeric chain end groups was characterized. Moreover, the number average molecular weight, isomers distribution and different isomer contents of PBD were acquired by NMR quantitative calculations, and the obtained results were in accordance with the results attained by other methods. [GRAPHICS] .