PURPOSE: To compare the findings of early periventricular leukomalacia on MR imaging and on US. MATERIALS AND METHODS: MR imaging was performed in 17 neonates in whom well-demarcated increased periventricular echogenicity was seen on sonography. One more patient was included during the same period because MR imaging of this patient showed a periventricular lesion not suspected on previous US. Initial sonography was performed within 6 days of birth and was followed up between one week and one month later. MR images were obtained within the first month of life. RESULTS: Twelve of 17 neonates showed abnormal periventricular signal intensities on MR imaging. Follow up sonography revealed cystic changes in two cases and heterogeneous hyperechogenicities in three. All patients except the two with cystic changes showed normal periventricular echogenicity on final sonography, On MR imaging,11 cases showed multifocal periventricular increased signals on T1-weighted images, and two cases showed mainly decreased signals representing cysts. Positive findings were more evident on T1-weighted than on T2-weighted image. CONCLUSION: on T1-weighted imaging, the characteristic finding of early periventricular leukomalacia was multifocal periventricular hyper or hypointensities, and hyperintense lesions were more common than hypointense. In the diagnosis of early noncystic periventricular leukomalacia, MR imaging was more objective than US.