Participants in advanced resuscitation courses are often expected to learn to perform intraosseous access (IO). But how many learning modalities are needed to achieve procedural confidence in IO? We distributed an online questionnaire to members of emergency medicine, paediatric and anaesthesiology societies in Scandinavia. The responders without real-life experience with IO (n=322) were classified as 'not confident' or 'confident' in IO. Of total responders 22.8% without training felt confident. Confidence increased to 74.8% after one training modality, 87.9% after two modalities, 98.7% after three modalities and 100% after four modalities (P<0.0001). Of total responders 89.5% who had 'workshop or similar training with hands-on experience' as sole teaching method was confident. Confidence in IO increases with the number of learning modalities. 'Workshop or similar training with hands-on experience' as single training modality seemed as effective as the combination of two modalities.