The brain is very sensitive to blood flow disruption, with abnormal flow patterns present in a wide range of neurovascular diseases, neurodegenerative conditions and lesions, such as tumours. Conventional methods to map brain blood flow, both through the arteries (angiography) and at the tissue level (perfusion), are often invasive and require ionising radiation, limiting their use in paediatrics, longitudinal imaging and research. In this talk I will describe recent developments in a non-invasive magnetic resonance imaging technique, arterial spin labelling, including vessel-selective blood flow mapping, simultaneous angiography and perfusion imaging and functional imaging, with some example applications in basic neuroscience and clinical research, including acute stroke, arteriovenous malformation, tonic pain and population neuroimaging.