The physical solubility of N2O in and the density and viscosity of aqueous piperazine solutions have been measured over a temperature range of (293.15 to 323.15) K for piperazine concentrations ranging from about (0.6 to 1.8) kmol(.)m(-3). Furthermore, the present study contains experimental surface tension data of aqueous piperazine solutions at temperatures of (293 and 313) K and at concentrations of (0.5, 1.0, and 1.5) kmol(.)m(-3) piperazine in water.