Background & Objectives: Neonatal mortality rate is a main indicator of hygienic development and recognition of the mortality causes is the first step for reduction of the mortality rate and promotion of this indicator. Therefore, in this study, the causes of neonatal mortality have been investigated in Ardabil medical university related hospitals.

  Methods: This study is a retrospective, cross-sectional and descriptive-analytical one that has been done on the bases of admission's units and filling the medical record form for all neonates who have been admitted to Alavi and Imam Khomeini hospitals in Ardabil from September 2006 to September 2007. The questions of forms consisted of infant’s sex, birth weight, gestational age, cause and age of death. The data were analyzed by SPSS software with utilizing T- test and Chi-Squares.

  Results: During this study, there were 1881 admissions of which there were 148 deaths (7.86%). The causes of mortality were hyaline membrane disease (HMD) (52.02%), sepsis (14.86%), pneumonia (9.45%), congenital anomaly (12.83%), asphyxia (7.43%) and meconium aspiration (3.37%). Among the dead neonates, 54.72% were male and others were female. There were 550 LBW neonates and 111 deaths in this group result of our study showed that mortality rate in LBW neonates was 20.18%. There were 578 preterm neonates and 122 deaths in this group prevalence of mortality rate in preterm neonates was 21.10%.

  Conclusion: Prematurity and low birth weight are the most important and fixed cases of infant mortality. The most common causes of mortality were hyaline membrane disease and sepsis. Therefore, the prevention of preterm labor for reduction of prematurity and its related complication recommended which may lead to decreased rate of neonatal mortality.