Summary : The n‐hexylamine‐initiated polymerization of Nε‐trifluoroacetyl‐L ‐lysine N‐carboxyanhydride in N,N‐dimethyformamide was studied by nonaqueous capillary electrophoresis. A polypeptide with a broad molecular weight distribution was obtained and side reactions were clearly identified for polymerization at room temperature. The possibility of living polymerization at 0 °C was demonstrated.