Experimental data on the density, d, and viscosity, eta, of ammonium oxalate aqueous solutions in the range of undersaturation and supersaturation are reported for solutions of saturation concentrations, c(s), between 0.36 M and 0.75 M. It was found that the temperature dependence of d for solutions of different saturation concentrations may be described by a first-order equation while that of eta may be described by an Arrhenius-type relation. Moreover, for solutions of particular saturation concentrations, c(s), both d and eta linearly increase with supersaturation.