NR stored for several months becomes progressively harder, a phenomenon called storage hardening affecting the processing properties of NR. The impact of lutoid stability on NR storage hardening was studied. Lutoid stability was determined by a qualitative parameter (lutoid integrity after centrifugation) and by a quantitative parameter (the bursting index or BI). The storage hardening of samples made from washed rubber particles (WRP) was compared to samples made from whole field latex. Lutoid bursting had a significant effect on the storage hardening of NR as shown by a significant correlation between the increase in Wallace plasticity (?P) after an accelerated storage hardening test and the BI of lutoids. The BI test appeared a better indicator of lutoid stability than the qualitative observation of lutoids after centrifugation. It was also shown that the ADS prepared with purified particles have a much lower PRI (70) than the controls ADS prepared with the entire latex (PRI=110).