The dilute aqueous solution behavior of regular amphiphilic comblike polymers with a polystyrene main chain and poly(ethylene oxide) (PEO) side chains, prepared by micellar polymerization has been investigated by means of multi-angle laser light scattering-size exclusion chromatography (MALLS-SEC), pyrene partitioning, and fluorescence spectroscopy. In 0.05 N NaCl solution, double logarithmic plots of 〈 S 2〉 z 1/2 of the comblike polymers with PEO chain length, n=50 against M w were found to be fitted by a smooth curve convex upward. The slope of the curve was about 0.8 7 for M w between 4×10 5 and 1×10 6 and about 0.56 for M w higher than 2×10 7. The experimental M w-dependence of 〈 S 2〉 z and particle scattering factor, P(θ) were quantitatively described by a wormlike chain model with persistence length, q=16. 8 nm. The persistence length of the comblike polymers was found to linearly increase with increasing PEO chain length.