The objective of this study is to identify the risk factors for neonatal thrombocytopenia among preterm infants. During a 4-year study period all consecutive, singleton preterm deliveries (between 27 and 35 weeks of gestation) were evaluated, and separate cohorts were compared - growth restricted (small-for-gestational-age; SGA) and appropriately grown (appropriate-for-gestational-age; AGA) infants. An initial comparison was done for the presence of thrombocytopenia (platelet count below 150,000/mL) and marked thrombocytopenia (below 100,000/mL). Following that, a comparison was made between the groups as determined by platelet count for various possible risk factors. Three hundred and five preterm infants were included in the study. Mean platelet count was significantly lower in the SGA group (p = 0.0009). Ninety-three neonates (31%) were thrombocytopenic and 212 infants with a normal platelet count served as controls. In the thrombocytopenic group, the rate of preeclampsia was significantly higher (p = 0.002). Thrombocytopenic infants had a significantly lower average gestational age at delivery (p = 0.002), lower birth weight (p = 0.0001), and low 5-minute Apgar score (p = 0.0002). They were more likely to suffer from intraventricular hemorrhage (IVH) (p = 0.04) and sepsis (p = 0.002). Growth restriction, lower gestational age and low 5-minute Apgar score (<7) were found to be significantly independent risk factors for marked thrombocytopenia, when analyzed separately. Growth restriction, lower gestational age at delivery, and low 5-minutes Apgar score are significantly associated with neonatal thrombocytopenia in preterm infants, which may lead to significant morbidity. Screening these high-risk groups for thrombocytopenia might be beneficial in terms of early diagnosis and management.