BACKGROUND Nasal valve collapse and especially internal nasal valve insufficiency is a common cause of nasal airway obstruction. This study compares the effects of spreader graft and overlapping lateral crural technique on rhinoplasty by rhinomanometry. METHODS Fifty patients were randomly assigned into two groups and underwent spreader graft or overlapping lateral crural technique. Objective assessment was performed by clinical examination and rhinomanometry before and after rhinoplasty. RESULTS Nasal obstruction had no significant difference before and after rhinoplasty and no significant difference was observed between surgical techniques. Right, left and total nasal flow and resistance were different before and after surgery but were not significant. Base of the nose was not significantly different between two groups, but nasal projection was 2 mm in the the group who underwent overlapping lateral crura technique and the difference was statistically significant. Our study showed that both overlapping lateral crura and spreader graft technique were beneficial in rhinoplasty and they could provide enough internal nasal valve support. The overlapping lateral crura was an appropriate surgical technique for tip projection in comparison to spreader graft. CONCLUSION The overlapping lateral crura technique was shown to be a better surgical way for tip projection in comparison to spreader graft.