An experimental study was carried out on drag reduction phenomena in turbulent pipe flow. Polyethylene oxide and polyacrylamide were extensively used as the drag reducing polymer additives. The onset wall stress at which the drag reduction begins decreased as pipe diameter and additive concentrations increased, showing a Reynolds number effect. Meanwhile, the laminar-to-turbulent transition was delayed and smoothed above a certain polymer concentration. The drag reduction increased with concentration and flow rate approaching asymptotic values, and decreased with pipe diameter for the same Reynolds number flow. The maximum drag reductions obtained were 88.9 % for polyethylene oxide and 84.5 % for polyacrylamide, respectively. These results were correlated by a phenomenological analysis to yield a single band curve. In respect to polymer degradation, the polyacrylamide showed better shear stability than the polyethylene oxide and thus the former expected to have a sharper molecular weight distribution which could not be proved by available GPC's.