The purpose of this study was to check the influence of extended setting time on permanent deformation for 5 vinyl polysiloxane materials (Flexceed, Imprint II Garant, Aquasil Ultra LV, AFFINIS PRECIOUS, Elite HD+) and 1 polyether (Impregum Soft). Specimens (n=10) were fabricated in a brass mold and loaded in tension with a crosshead speed of 200 mm/min to 80% strain. Change in length measured after 2 hours. Influence of storage time was tested by t test. Correlation between tests was evaluated using Pearson’s correlation coefficient.The results of the present study showed that permanent deformation in Impregum Soft was reduced from 2.53% to 0.98%. For Flexceed it reduced from 1.69% to 0.896% and from 0.88% to 0.35% in case of Elite HD+. It was concluded that extending the intraoral time can reduce permanent deformation in case of Flexceed (GC), Elite HD+ and Impregum Soft (3M) polyether.