Background:One of the major disadvantages associated with using composites is polymerization shrinkage; stresses are generated at the margins, and if these stresses exceed the bond strength, microleakage occurs at the tooth restoration interface which causes ingress of cariogenic bacteria, post-operative sensitivity, and secondary caries. LED offers several curing modes: constant cure, ramped cure, and soft start cure. It is claimed that soft start polymerization mode produces less polymerization shrinkage and consequently less postoperative sensitivity.Objective:To compare the postoperative sensitivity in Class V composite restorations using soft start and constant LED curing modes.Materials and Methods:Using the appropriate burrs cavity was prepared and filled with composite Z 100(3M-ESPE) using a incremental technique. Each increment of 2 mm was cured either with soft start or constant cure. All patients were evaluated at day 2 for postoperative sensitivity.Results and Discussion:Out of 124 restorations that were placed, only three restorations presented with postoperative sensitivity, each one being in mild, moderate, and severe categories, respectively. No relationship was seen between the sensitivity and tooth type. There was no statistically significant difference in postoperative sensitivity in either of the treatment modalities (constant or soft start).Conclusion:We conclude that restorations placed with the soft start curing technique did not show significant changes in postoperative sensitivity when compared to the constant curing technique.