The standard k-epsilon model and a second-order Reynolds stress model (RSM) are used to investigate variable density effects in axisymmetric turbulent jets. Without buoyancy, both models predict no effect of the varying density on the far Field turbulence parameters and the classical effective diameter concept works for the decay rates. No conclusive disagreement with experimental data is observed. Effects of turbulence production due to buoyancy are found to be small compared to the effect of the mean buoyancy term in the momentum equation. However, this turbulence product:on has a large influence on the axial scalar flux, for which the experimental trend is predicted with the second-order model but not at all with the k-epsilon model.