The results of studies of phase transitions of KNO3, embedded in carbon nanotubes, are presented. It is shown that for KNO3 particles in nanotubes, a narrowing of the tempera-ture range of the existence of the ferroelectric phase is observed, similarly to what hap-pens in ferroelectric semiconductors. The results obtained indicate that the external screening from the side of the conducting matrix acts similarly to the screening of spon-taneous polarization in conducting ferroelectrics.