This paper describes an implementation of the Infrastructure-as-a-Service (IaaS) concept for scientific computing and seven service pilot implementations with requirements from biomedical use cases at the CSC - IT Center for Science. The key service design requirements were enabling the use of any scientific software environment the use cases needed to succeed, and delivering the distributed infrastructure ICT resources seamlessly with the local ICT resources for the scientist users. The service concept targets the IT administrators at research organisations and delivers virtualised compute cluster and storage capacity via private network solutions. The virtualised resources can become part of the local cluster as virtual nodes and they can share the same file system as the physical nodes assuming the network performance is sufficient. Extension of the local resources can then be made transparent to enable an easy infrastructure uptake to the scientist end-users. Based on 20 months of service piloting most of the biomedical organisations express a sustained and growing need for the distributed compute and storage resources delivered with the IaaS. We conclude that a successful implementation of the IaaS can improve access and reduce the effort to run expensive ICT infrastructure needed for biomedical research.