Main theme of present article is to investigate the peristaltic activity of MHD flow of Williamson nano-fluid saturating porous space. Inner tube is fixed while the outer tube is subjected to sinusoidal traveling wave. Unlike the traditional approach, modified Darcy's law characterizes the flow of Williamson fluid. Both tubes with reference to blood arterial flow are considered flexible. No-slip condition for velocity is employed. Convective conditions of heat and mass transfer are invoked. Nanofluid flow using Buongiorno model that considers the effects of both Brownian motion parameter and thermophoresis parameter are also under consideration. The nonlinear differential systems are reduced for large wavelength analysis. Numerical study is performed for the resulting problems. Impacts of various emerging parameters for velocity, temperature, nanoparticle volume fraction and heat transfer rate are examined. A comparative study reveals good agreement with existing limiting study. (C) 2017 Elsevier Ltd. All rights reserved.