[en] An accurate, sensitive and reliable radioanalytical procedure for determining α-emitting nuclides of radium in water samples has been tested using ²²⁶Ra standard reference sources. Radium is chemically separated together with barium from all other components and precipitated by acetic acid in presence of seeding suspension to produce fine crystals to minimize self absorption of the α-particles in getting out of the crystal lattice. The precipitate is mounted on a membrane filter and analyzed using α-spectrometer. Sensitivity, precision and accuracy of the technique are thoroughly investigated. Representative data for some water samples are given. (orig.)