The coil-globule transition behavior of sodium poly(styrene sulfonate) (NaPSS) (M-w = 1.2 x 10(6) g/mol) in 4.17 M aqueous NaCl solution has been studied by dynamic light scattering. The polymer dimensions show a smooth and continuous contraction below the reference temperature (18 degreesC). The hydrodynamic radius ([R-h]) of NaPSS in this system was reduced from 13.1 nm (18 degreesC) to 9.1 nm at 10 degreesC. At the latter temperature the polymer segment volume fraction was calculated to be 0.58. The contraction for this and other NaPSS samples investigated in this study is somewhat limited because under these high ionic strength conditions the polymer chains already contracted as a result of the screening effect of the ions.