Two series of solution polymerizations of propene were conducted : (i) using three different methylaluminoxane (MAO)-activated zirconocenes, rac-Et(Ind)(2)ZrCl2 (EI), rac-Me2Si(Ind)(2)ZrCl2 (MI), and rac-Me2Si(Benz-[e]-Ind)(2)ZrCl2 (MBI), at the same temperature (30 degrees C) and varying propene pressure from 0.15 to 1.1 bar and (ii) using rac-Me2Si(Benz-[e]-Ind)(2)ZrCl2 (MBI) at the propene partial pressure 1.1 bar and at a range of temperatures from 30 to 100 degrees C (Ind = Indenyl). H-1 and C-13 NMR investigation of the unsaturated chain end groups in these samples was performed, with particular attention being paid to (i) a detailed re-examination of the NMR assignments reported in the literature, (ii) the distinction between unsaturated species formed during the polymerization reactions and those formed afterward due to thermal treatment (i.e. during the NMR experiments), (iii) determination of the dependence of the quantities of different types of terminals on the polymerization conditions (temperature and monomer partial pressure). It was shown that four unsaturated chain end groups are formed during polymerization, that is, vinylidene, 2-butenyl, allyl, and the previously unidentified 4-butenyl terminals. In the oligomeric fraction of samples, no further types of unsaturated terminals were observed. Two further types of unsaturated groups observed, isobutenyl and the unidentified species X, were not formed during polymerization but, at least prevalently, afterward during the high-temperature NMR experiments. A previously unidentified regiomisinsertion, lateral n-butyl, is also described.