Viscosity measurements were carried out in methyl ethyl ketone (MEK) and dimethyl formamide (DMF) for rubber seed oil alkyds having oil content of 20 (I), 30 (II), 35 (III), 40 (IV), 50 (V), and 60% (VI). Viscosity molecular weights, intrinsic viscosities, and viscosity parameters K and alpha, characteristic for both polymers and solvents, were determined. Generally, solubility properties were found to depend on molecular weight and polarity of the alkyds and solvent. Intrinsic viscosities of the alkyds were larger in DMF than in MEK, suggesting DMF to be a better solvent than MEK for rubber seed oil alkyds. Molecular weights determined for the alkyds range from 441 for sample III to 1323 for sample V. The viscosity molecular weights are in reasonable agreement with the values determined for samples II-V in MEK and samples I-IV in DMF. The values of Huggin＇s constant for these alkyds were also determined. Data reported also suggest that rubber seed oil alkyds tend to tolerate relatively basic solvent, such as DMF. Fractionation of the alkyds was considered to be in respect of molecular weight and polarity of the alkyds, and results show that low-molecular-weight species constitute greater proportion of the alkyds.