The densities of the aqueous solutions of poly(ethylene glycol) 2000 (PEG 2000), and its aqueous mixtures with electrolytes and nonelectrolytes, poly(ethylene glycol) 2000 + NaNO₃, poly(ethylene glycol) 2000 + sucrose, and poly(ethylene glycol) 2000 + sucrose + NaCl of various compositions have been measured at 20, 25 and 30°C. The density data of the aqueous binary solutions of PEG 2000 up to 0.5 molal have been fitted to a density–molality polynomial. The isopycnotic mixing rule (same density) has been used to predict the densities of the aqueous multicomponent solutions. The predicted and observed densities are in good agreement (overall average error percentage of 0.036%).