Introduction Neonates with hypoxic ischemic encephalopathy (HIE) who undergo therapeutic hypothermia (TH) remain at high risk for electrographic seizures (ES) that frequently lack clinical signs. These subclinical seizures necessitate the use of resource-intensive continuous video-EEG monitoring (cEEG) for their detection. We assessed the prevalence, timing and predictors of ES among babies with HIE who underwent TH, noting subclinical ES in particular. Methods Patients and Setting – In our neonatal intensive care unit, neonates ⩾36 weeks gestation with HIE may receive 72 h of whole-body cooling to 33–34 °C within 6 h after birth. CEEG is maintained throughout cooling and for at least six hours during rewarming. Design – We queried our prospectively maintained REDCap ICU cEEG database to identify all neonates with HIE who underwent TH during the years 2015–2017. We then abstracted detailed data from these patients’ daily cEEG reports that had been performed daily according to ACNS guidelines. Descriptive statistics were performed on pertinent clinical and EEG variables, followed by a between-group comparison of those babies with and without ES. Results We identified 36 neonates (male = 23) who underwent TH. Of these, 16 (44%) experienced ES. All neonates with ES experienced some subclinical seizures, while 12/16 (75%) experienced subclinical seizures exclusively. Status epilepticus was identified in 5/36 neonates (14%), including 3 with subclinical ES exclusively. The timing of the first ES was as follows: first hour = 6 (37.5%); 1–24 h = 7 (44%); 24–72 h = 1 (6%); 72–78 h (rewarming) = 2 (12.5%). A variety of obstetric, neonatal and neuroimaging variables (including Apgar scores, initial pH, and extent of post cooling MRI abnormalities) were similar between the groups of neonates with and without ES. The absence of background variability/reactivity, the presence of excessive negative sharp transients, and the presence of excessive background discontinuity or a burst suppression pattern was not associated with ES. Babies with ES had a longer median duration of background discontinuity compared to those without ES (29 s vs. 12 s) but the difference was not significant. However, the presence of brief rhythmic discharges (p = 0.018), focal repetitive discharges (p = 0.011) and excessive positive sharp transients (p = 0.0001) were associated with ES. Two neonates died including one with ES but not status epilepticus. Conclusion Among neonates with HIE who undergo TH, seizures are common and most frequently subclinical. They can occur at any point throughout cooling or during rewarming. Without cEEG, status epilepticus will be completely missed in some patients. While clinical variables are unreliable at predicting those babies with ES, some EEG variables are highly associated with ES, and may help to allocate scarce cEEG resources.