Brain ultrasound (US) represents the first line imaging modality for the evaluation of the neonatal brain. The main advantages of the technique are safety, performance at bed side, possibility for serial imaging without sedation, real-time information, coupling with colour Doppler and low cost. Anterior fontanel is the classic acoustic window but mastoid and posterior fontanel approaches are increasingly being used for better evaluation of the occipital lobes and the posterior fossa structures. Tranducers of different frequencies are routinely used to optimise imaging and increase lesion detectability. Intubated ventilated preterm babies are examined in the incubator and ischaemic-haemorrhagic brain disease can be detected at very early stages. Early periventricular leukomalacia (PVL) appearing as periventricular hyperchogenicity with sharp or hazy speculated margins and early periventricular venous infarct appearing as fan-shaped paraventricular echogenicity associated with flow disappearance in the terminal vein are important US and colour Doppler findings appearing before detection of any abnormality on MRI. Infectious haemorrhagic infarcts appearing initially as punctuate hyperechogenic lesions and progressing into microcystic lesions are almost never detected by MRI. Increased echogenicity is detected at the early stages of less common acquired lesions such as gangliothalamic ischaemia and cortical necrosis. Intraventricular haemorrhage can be easily detected by US. Colour Doppler by depicting moving echoes in the aqueduct of Sylvius is very helpful in the detection of haemorrhage at its very early stages and in the differential diagnosis between intraventricular and subependymal haemmorhage. Brain maturation-myelination and long-term follow-up of perinatal lesions should be performed with MRI. Learning Objectives: