The bodily decline that occurs with advancing age strongly impacts on the prospects for future health and life expectancy. Despite the profound role of age in disease etiology, knowledge about the molecular mechanisms driving the process of ageing in humans is limited. Here we used an integrative network-based approach for combining multiple large-scale expression studies in blood (2,539 individuals) with Protein-Protein Interaction (PPI) data for the detection of consistently co-expressed PPI modules that may reflect key processes that change throughout the course of normative ageing. Module detection followed by a meta-analysis on chronological age identified fifteen consistently co-expressed PPI modules associated with chronological age, including a highly significant module (p=3.5×10(-38) ) enriched for "T-cell activation" marking age-associated shifts in lymphocyte blood cell counts (R(2) =0.603; p=1.9×10(-10) ). Adjusting the analysis in the compendium for the "T-cell activation" module showed five consistently co-expressed PPI modules that robustly associated with chronological age and included modules enriched for "Translational elongation", "Cytolysis" and "DNA metabolic process". In an independent study of 3,535 individuals, four out of five modules consistently associated with chronological age, underpinning the robustness of the approach. We found three out of five modules to be significantly enriched with ageing-related genes, as defined by the GenAge database, and association with prospective survival at high ages for one of the modules including ASF1A. The hereby-detected age associated and consistently co-expressed PPI modules therefore may provide a molecular basis for future research into mechanisms underlying human ageing. This article is protected by copyright. All rights reserved.