The solution behavior of arborescent (highly branched) polymers was examined in terms of Az variation with polymer structure, solvent type, and temperature. Two series of graft polymers in three successive generations were examined, with side chains of either 5000 (S05 series) or 30 000 (S30 series). Scaling relationships A(2) proportional to M-w(a) were found for both series, with a = -0.94 or -0.97, consistent with rigid-sphere behavior. Temperature-dependent measurements were carried out in cyclohexane and in toluene, to allow decomposition of A(2) into its enthalpy (A(2,H)) and entropy (A(2,S)) components. In cyclohexane, the magnitudes Of A(2,H) and A(2,S) were mainly affected by the branching functionality of the polymers, and less significantly by the molecular weight of the side chains. Furthermore, the temperature dependence of A(2) in bath solvents was found to be more strongly influenced by branching functionality than by the molecular weight of the polymers. Variations in the Theta temperature for polymers of low branching functionality in cyclohexane are consistent with the trends observed in star-branched polymers. However, no measurable Theta temperature was observed for a polymer with a branching functionality f(w) = 180.