Miscibility studies have been conducted on solutions of blends of polyacrylamide (PAAm) and polyethylene glycol (PEG) over an extended range of concentrations in water. The ultrasonic velocity, viscosity, density, and refractive index of the blends have been measured for different compositions viz., 0/100, 10/90, 20/80, 30/70, 40/60, 50/50, 60/40, 70/30, 80/30, 90/10, and 100/0 of PAAm/PEG blends at 30 degrees C. The interaction parameters such as mu and alpha have been evaluated using the viscosity data to probe the miscibility. The obtained results have been confirmed by the ultrasonic velocity, density, and refractive index. (c) 2007 Wiley Periodicals, Inc.