The concept of affordance views IT as socio-technical artefacts and affordances as bridges between artefacts and their users, and has been defined as what an individual, group or organization with a particular purpose can do with a technology. The present research examines IT affordances via a mul-ti-level perspective, with a focus on the relationship between feature-level and system-level affordanc-es. More specifically, the present study examines how macro (system) level IT affordances emerge from micro (feature) level affordances via an exploratory case study approach in an e-health context to analyse data from 16 asthma patients who used a web-based, user-centric portal to self-manage their asthma. The results of our analysis suggest that system-level and feature-level affordances of the portal were not necessarily the same for each patient, and the system-level affordances played an es-sential role in determining their attitudes and behaviors toward the portal.