In the present work, a mathematical model of nonlinear blood flow through a stenosed artery is developed. Treating the artery as a stenosed, elastic, thin walled long tube and using the reductive perturbation method, the propagation of weakly nonlinear waves in such a fluid-filled elastic tube is studied. By considering the blood as an incompressible inviscid fluid, the evolution equation is obtained as the extended Stochastic Korteweg-de Vries equation. Progressive wave solution to this evolution equation is obtained and effect of stenosis on the wave profile and the wave speed is discussed. (c) 2005 Elsevier Ltd. All rights reserved.