Many water soluble polysaccharides are ionic and present original electrostatic properties depending on the structure of the polymer but also on the ionic concentration. Some of these polysaccharides originate from bacterial strains producing very stereoregular polymers being good models for fundamental research and to establish the relation between molecular structure and properties. In this paper, a review of our main results obtained on these polysaccharides is presented. It relates to electrostatic interactions in the different systems investigated. First we studied the electrostatic interactions between polyion and counterions and the ionic selectivity which can lead in some cases to gel formation. Then, one investigated the electrostatic intrachain interactions which play a role on the conformations and their stabilities but also on the dimensions of the chains. The ionic polysaccharides are characterized by their intrinsic persistence length, reflecting their stiffness. At end, the interchain electrostatic interactions were also demonstrated from neutron and light scattering and viscosity measurements where specific electrostatic peaks appear.