The regio- and stereocontrolled functionalisation of carbon-carbon double bonds bears enormous potential in organic synthesis. This area has been extensively studied and reviewed as alkenes are amongst the most important starting materials for synthetic chemists, accessible in many varieties and in large quantities. We focus in this tutorial review only on recent developments using iodine electrophiles for the functionalisation of alkenes although transition-mediated reactions and functionalisations with chalcogen electrophiles also play an important role. New synthetic applications using this methodology showing scope and limitations of iodine-mediated processes also within the context of other electrophilic reactions are highlighted.