The purpose of this work is to compare DNA condensation induced by small multivalent ions and polycations. DNA complexes with trivalent ions Fe ³⁺, La³⁺, [Co(NH₃)₆]³⁺, spermidine and cationic polymers in a solution were investigated. The influence of cations on the volume, persistent length, and secondary structure of DNA was studied. A comparison of DNA packaging induced by trivalent ions and polycations was made. DNA complexes with trivalent metal ions and polycations were characterized by means of low gradient viscometry, dynamic light scattering, circular dichroism, UV spectrometry, flow birefringence, and atomic force microscopy.