Purpose: This study is designed to compare the iron status between small for gestational age (SGA) and appropriate for gestational age (AGA) infants at birth. Methods: We retrospectively reviewed the clinical data of 904 newborn infants admitting neonatal intensive care unit between March 2014 and April 2017. Infants’ blood samples were taken within 6 h of delivery. Result: A total 125 SGA (gestational age (GA) 36.3 ± 3.2, birth weight (BW) 1,975 ± 594.5 g) and 779 AGA (GA 35.1 ± 3.7, BW 2,420.3 ± 768.7 g) were recruited in this study. SGA infants had higher Hb (16.7 ± 2.0 vs. 16.0 ± 3.2 g/㎗, p0.05), Hct (50.8 ± 6.0 vs. 47.6 ± 6.3 %, p0.05) and lower platelet count (236.2 ± 80 x 103/㎕ vs. 257.9 ± 64.3 x 103, p0.05) than AGA infants at birth. Maternal serum ferritin levels were higher in SGA infants compared with AGA infants (58.6 ± 141.1 vs. 29.9 ± 42.2 ng/㎖, p0.05). There was no difference in the serum ferritin between SGA and AGA infants at birth (166.2 ± 129.2 vs. 186.2 ± 169.6 ng/㎖) and the SGA groups rather had a lower mean value. After adjusting for gestational age, SGA infants has lower ferritin levels than AGA infants [mean (95% CI);146.2 (117.4-174.9) vs 189.7 (178.3-201.1), p0.05]. Total body iron store was also lower in SGA infants compared with AGA ones (181.2±41.5 vs 201.8 ± 49.2, p0.05). Conclusion: This study showed that the SGA infants haveqne lower ferritin and total body iron store compared with the AGA infants. Iron deficiency should be monitoring in these infants during follow-up.