The doctoral thesis is devoted to producing and investigation of lead-free ferroelectric ceramics based on potassium sodium niobate. The effect of ceramic modification on the density, dielectric, ferroelectric, electromechanical properties are evaluated. The Patent of the Republic of Latvia is received for new solid solutions that are described in doctoral thesis. Literature review gives an overview about lead-free ceramics, especially potassium sodium niobates. The aspects of conventional ceramic processing technology are examined and new chemical methods of ceramic powder preparation are mentioned. The influence of ceramic processing conditions and the chemical composition on the microstructure, dielectric and electromechanical properties is evaluated. The experimental part of the thesis describes raw materials, sample preparation, as well as methods and equipment used to analyse the material properties. The last chapter of the doctoral thesis the results are analysed and the assassment is given. The achieved results are given in the conclusion. In the references list the sources of used in the work are mentioned on the period from 1971 till 2012. Dissertation theses are written in Latvian, consist of 105 pages. The theses contains 60 pictures, 7 tables and 126 references.