Association of a beta-cyclodextrin polymer, a cationic surfactant, and an anionic polymer leads to ternary complexes involving both inclusion complexes and electrostatic interactions. Polyanions of different natures and architectures have been used: sodium polystyrene sulfonate (NaPSS), molecular weight 70 000, has a flexible and hydrophobic backbone whereas sodium dextran sulfate (NaDxS) (molecular weights 10 000 and 40 000) are hydrophilic and have branched structures. Phase diagrams have been established by mixing a beta-cyclodextrin polymer (poly(beta-CD)), a cationic surfactant (dodecyltrimethylammonium chloride, DTAC), and a polyanion (sodium salt polystyrene sulfonate, NaPSS) in water. For one of the soluble mixtures, the formation of poly(beta-CD)/DTAC/NaPSS ternary complexes has been proved by using viscometry and small-angle neutron scattering. For fixed concentrations of both polymers, the structural properties of the ternary complexes have been studied as a function of the cationic surfactant concentration in the bulk solution. A change in the overall structure of the complexes has been observed, from diffuse aggregates at low N-DTAC to dense aggregates at higher concentration. The properties of the ternary complexes have been shown to depend on the polyanion nature and characteristics. Ternary complexes with NaPSS (M-w = 70 kg(.)mol(-1)) are soluble to higher DTAC concentrations than those with NaDxS I (M = 10 kg(.)mol(-1)), the latter being more soluble than those with NaDxS 2 (M, = 40 kg(.)mol(-1)). Neutron scattering experiments have shown that the inner structure of the aggregates are inhomogeneous (the elementary particles have a core-shell structure) at DTAC concentrations lower than a critical value (N-DTAC(crit)) whatever the polyanion nature. At larger DTAC concentrations, compact and entangled inner structures are obtained with NaDxS 1 (of low molecular weight) when core-shell inner structures are obtained with NaDxS 2 and NaPSS (of higher molecular weight). Analysis at larger length scales allowed characterization of the overall structure of the aggregates. The flexible chains of NaPSS are able to maximize the electrostatic interactions by wrapping up the poly(beta-CD)/DTAC elementary particles, whereas the more rigid NaDxS involves an aggregation mechanism between the same particles.