Different polyetherketones (PEK) based on olygoketonephenolphthaleines (OKPP) with different condensation degrees and dichloranhydrides of isophthalic and terephthalic acids were obtained by means of an aceptor-catalytic polycondensation. The correlation between the composition of the initial olygoketones and the properties of the resultant polyetherketones was established. Some of the physico-chemical properties of PEK were also investigated. It was shown that as the initial length of OKPP increased the yield strength, heat stability, the glass transition temperature and melt temperature increased.