Structural health monitoring of delamination in polymer based composite laminates is an important problem for ensuring safe operation of composite based structures. The use of carbon nanofillers dispersed in polymeric matrix has shown promise as a way of structural health monitoring by correlating changes in electrical resistance with the accumulated damage in the composite. In the present work we use a new approach employing carbon nanostructure (CNS) buckypapers (BP) to prepare glass fiber/epoxy composite laminates with enhanced resistance to delamination and damage monitoring capability. Selective reinforcement and structural health monitoring in composite laminates is achieved by introducing the CNS-BS at the interlaminar region using a method of frictional sliding. The changes in the compliance of short beam samples subjected to fatigue loading in the three point bending configuration due to delamination were correlated with the changes in electrical resistance. Delamination in the sample is manifested in increased electrical resistance caused by the breakage of the conductive interlaminar layer with carbon nanofillers. The electrical resistance results show correspondence with delamination crack nucleation, followed by stable and unstable crack growth. Crack propagation in the three point bending configuration shows a combination of opening and sliding modes of fracture. The sliding, (Mode II) resulted in partial closing of the delamination cracks during cycling. The mechanics of crack closing during fatigue and in the unloaded configuration was also studied using finite element analysis to help understand the experimentally observed partial recovery of the electrical conductivity. The proposed method of structural health monitoring offers a promising technique for detecting and examining delamination damage in composite laminates in fatigue life. Keywords: structural health monitoring, carbon nanostructures, delamination, electrical resistance, fatigue life