This document discusses issues in costing cross-cutting health systems strengthening (HSS) interventions in Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM) proposals, using Afghanistan as an example. It outlines areas typically covered by HSS, such as human resources, infrastructure, and health products. It also notes challenges in Afghanistan, including a lack of local expertise in costing, difficulty linking investments to outcomes, inadequate proposal preparation, and reliance on salary budgets. Standardized unit costing is difficult for HSS due to the wide range of services involved and lack of national costing strategies and data.