OBJECTIVE: To understand the relationship of the grading of periventricular echodensities (PVE) with the morbidity and the occurrence time of periventricular white matter cystic lesions in preterm infants. METHODS: A retrospective, single-centre cohort study of 120 preterm infants with PVE diagnosed by ultrasonography between February 2005 and May 2008 was performed. The infants had a median gestational age of 32 weeks and a median birth weight of 2 230 g. RESULTS: Fifty-two infants (43%) were diagnosed as having PVE I, 42 infants (35%) having PVE II, and 26 infants (22%) having PVE III. The grading of PVE was closely related to birth weight, but not with gestational age. The total morbidity of periventricular white matter cystic lesions was 24% (29/120). The morbidity of the cystic lesions in PVE III patients (65%) was significantly higher than that in PVE II patients (21%) (P<0.01). The PVE III patients developed the cystic lesions earlier than the PVE II patients. CONCLUSIONS: The grading of PVE is closely related to the morbidity and the occurrence time of periventricular white matter cystic lesions in preterm infants.［Chin J Contemp Pediatr, 2009, 11 (2):104-106］