The behavior of a high molecular weight sodium poly[bis(carboxylatophenoxy)phosphazene] (NaPCPP) polyelectrolyte sample in aqueous solution has been investigated by means of viscosity, conductivity, sodium counterion potentiometric "activity coefficient" (gamma(+)) measurements, and Na-23-NMR experiments. The set of data clearly and consistently points out the peculiar polyelectrolytic behavior of NaPCPP in water. In our opinion, this is essentially due to the pal tial hydrophobic character of flexible NaPCPP chains which would easily "entangle" even at low concentrations in water and, in addition, would give rise to "entanglement collapse" with increasing solution temperature.