The tensile creep behavior of polystyrene was studied at elevated temperature of 70 to 240°C. This paper will describe in detail experimental techniques and apparatus to obtain the zero shear viscosity of the polymer in this temperature range. Data will be compared with similar information obtained by other experimental techniques. Possible explanations for the discrepancies in the two sets of data are discussed. The paper will indicate, however will not discuss in detail how one can obtain melt elasticity, creep function, and compliance function of an amorphous polymer in the temperature range of 70 to 240°C, by creep experiments.