Light scattering experiments were undertaken to study binding of the Max transcription factor to its E-box DNA recognition sequence. Translational diffusion coefficients were measured and the average hydrodynamic radii (Rh) of complexes calculated using the Stokes-Einstein equation. We detected both dimerization of Max and the formation of a stable complex with its E-box DNA target. These results demonstrate the applicability of Dynamic Light Scattering for measuring protein-DNA interactions.