Normalisation of blood LDH level is associated with improved survival in many studies conducted in adults, in children and neonate. The study aimed to estimate the LDH for different pediatrics age groups. An observational study was conducted at Pediatrics ward, Abu Ghraib General Hospital, from January 2018 to December 2019. Study sample included 250 children, their age ranged from 1 day to 16 years. Children of both gender with these age groups admitted to ward, and blood LDH were calculated. The maternal history, fever, umbilical infection, SOB, hypoxia, sepsis, and respiratory distress syndrome (RDS) were documented accordingly. LDH measured as followed: New born: 160 to 450 units per litre (units/L) and child: 60 to 170 units/L. We divided sample to two-groups, newborn babies (1 day to 1 year) and chid (>1 year to 16 years), and the study variables were documented. The LDH concentration and variables correlation calculated. The prognostic value of serial serum LDH monitoring for predicting morbidity and mortality in sick children is confirmed. There is a correlation, although very clear, between the plasma LDH levels with infection, asphyxia, and RDS.