Introduction: Regarding the importance of measurements to reduce neonatal mortality rate, this study aimed to assess the causes of neonatal mortality and its related factors in two hospitals in Qazvin.Methods: This was a cross-sectional study in which the medical files of the NICUs of Ghods and Kosar hospitals in Qazvin were assessed during April to September 2010. Data were assessed according to some related factors including gender, gestational age, birth weight, APGAR score, mothers' age, neonatal age, cause of death, maternal past medical history, and complications of pregnancy and delivery.Results: From 225 admissions, 50 deaths occurred during the study (neonatal mortality rate: 22.2%). The causes of mortality were respiratory distress syndrome (26%), sepsis and its complication (DIC) (40%), asphyxia (16%), congenital heart disease (14%), and other causes (4%). It was also revealed that the causes of death in low birth weight neonates were similar to those of premature neonates. There were significant relationships between death rate and gestational age, birth weight, APGAR score, age at the time of death, and complications of pregnancy.Conclusion: The most common causes of mortality were respiratory distress syndrome and sepsis.Prevention of preterm labor is recommended to reduce premature births, its related complications and consequently, neonatal mortality rate.