The segmented copolymer poly(ethylene terephthalate-co-caprolactone (PET-PCL)) was successfully characterized by using a combination of static and dynamic laser lightscattering (LLS). According to the Bushuk-Benoitlight-scattering theory, at least three solvents with different refractive index increments have to be used to determine the weight-average molecular weight (M(w)). Unfortunately,for samples with higher contents of PET (>50%), we were able to find only two such solvents. Thus, we were forced to adopt a modified LLS method wherein only two solvents were required. For each solvent, we first measured the apparent weight-average molecular weight (M(w,app)) from static LLS. Then M(w,app) was used as a constraint to convert the line-width distribution from dynamic LLS into an apparent molecular weight distribution. Finally, after combining the two apparent molecular weight distributions, we determined not only the molecular weight distribution but also an estimate of the copolymer chain composition distribution. For samples with lower contents of PET, the M(w)’s, calculated from such obtained molecular weight distributions are comparable to those from-the traditional three-solvent static LLS method.