Background: Smooth muscle cell (SMC)‐rich intima is a morphological feature of atherosclerotic lesions that is observed in eroded plaque and spastic arteries. Arteries with SMC‐rich intima are susceptible to vasoconstriction or vasospasm against some vasoactive agents. Objective: The present study evaluates the contribution of SMC‐rich intima to thrombogenic vasoconstriction. Methods: We established SMC‐rich neointima by damaging rabbit femoral arteries using balloons and then measured the isometric tension of the femoral strips against 5‐hydroxytryptamine (5‐HT), adenosine diphosphate, adenosine triphosphate and thrombin. Results: Among these agents, only 5‐HT induced a hypercontractile response of the injured arteries with SMC‐rich neointima, compared with non‐injured arteries. Smooth muscle cells of both the neointima and media expressed 5‐HT2A receptor, and sarpogrelate, a selective 5‐HT2A receptor antagonist significantly inhibited the hypercontraction. Furthermore, 5‐HT induced contraction of separated neointima and hypercontraction of separated media compared with non‐injured media. Sarpogrelate and fasudil, a specific Rho‐kinase inhibitor, significantly suppressed such contraction of both the neointima and media of injured arteries. Conclusions: These results suggest that 5‐HT plays a crucial role in thrombogenic vasoconstriction, and that SMC‐rich intima as well as media directly contributes to the hypercontractile response of atherosclerotic vessels through the 5‐HT2A receptor and the Rho‐kinase pathway.