Peristaltic transport of electrically conducting blood through a permeable microvessel is investigated by considering the Casson model in the presence of an external magnetic field. The reabsorption process across the permeable microvessel wall is regarded to govern by Starling's hypothesis. Under the long wavelength approximation and low-Reynolds number assumption, the nonlinear governing equations along with the boundary conditions are solved using a perturbation technique. Starling's hypothesis at the microvessel wall provides a second-order ordinary differential equation to be solved numerically for pressure distribution which in turn gives the stream function and temperature field. Also, the location of the interface between the plug and core regions is obtained from the axial velocity. Due to an increasing reabsorption process, the axial velocity is found to increase initially but decreases near the outlet. The temperature is appreciably intensified by virtue of the Joule heating produced due to the electrical conductivity of blood.