Objective To evaluate safety,efficacy and complications of the implantation of Ommaya reservoir in very low birth weight infants with posthemorrhagic hydrocephalus (PHH).Methods 12 consecutively very low birth weight infants presenting with progressive ventricular dilatation caused by intra - ventricular haemorrhage ( IVH ) grades Ⅲ to Ⅳ were operated for implantation of an intra - ventricular catheter connected to a sub - cutaneous Ommaya reservoir from January 2005 to June 2011.Cerebrospinal fluid draining frequency,intermittent draining time and draining volume were conducted according to clinical manifestations and echographic follow - up,and the complications were observed postoperatively.The patients who presented a progression of the ventricular dilatation were finally operated for VP shunt implant according to the CT/MRI findings.Results 12 very low birth weight infants with PHH were treated with the placement of an Ommaya reservoir.8 had grade Ⅲ,and 4 had grade Ⅳ IVH.The mean gestational age was 29.1 weeks (26 -32) and birth weight was 1023g (770 - 1450) at birth.The mean age when reservoir implanted was 17.7 (13 -23) days and body weight was 1126g(890- 1560).One patient died of pulmonary complications during the study period.Out of the 11 survivors,7 did not develop progressive ventricular dilatation,and 3/7 reservoirs were removed; 4 developed progressive hydrocephalus were implanted with a ventriculoperitoneal shunts,and the reservoirs were removed.Postsurgical major complications (including skin dehiscence,CSF leak,CSF infection,ventricular hemorrhage) occurred in 50％ of all patients.Among these,skin dehiscence and CSF leak occurred in 3,CSF infection in 2,significant secondary hemorrhage in 1.Conclusions The placement of Ommaya reservoir and serial tapping in very low birth weight infants with PHH is a safe,feasible,and effective method with advantages of preventing the development of hydrocephalus and avoiding the placement of a permanent preoperative shunt in some patients.Despite a relatively high complication rate,modified techniques may reduce these complications.