BACKGROUND: International guidelines for resuscitation recommend using positive end-expiratory pressure (PEEP) during ventilation of preterm newborns. Reliable PEEP-valves for self-inflating bags have been lacking, and effects of PEEP during resuscitation of term newborns are insufficiently studied. The objective was to determine if adding a new PEEP valve to the bag-mask during resuscitation of term and near-term newborns could improve heart rate response. METHODS: This randomized controlled trial was performed at Haydom Lutheran Hospital in Tanzania (September 2016 to June 2018). Helping Babies Breathe–trained midwives performed newborn resuscitation using self-inflating bags with or without a new, integrated PEEP valve. All live-born newborns who received bag-mask ventilation at birth were eligible. Heart rate response measured by ECG was the primary outcome, and clinical outcome and ventilation data were recorded. RESULTS: Among 417 included newborns (median birth weight 3200 g), 206 were ventilated without and 211 with PEEP. We found no difference in heart rate response. Median (interquartile range) measured PEEP in the PEEP group was 4.7 (2.0–5.6) millibar. The PEEP group received lower tidal volumes (4.9 [1.9–8.2] vs 6.3 [3.9–10.5] mL/kg; P = .02) and had borderline lower expired CO2 (2.9 [1.5–4.3] vs 3.3 [1.9–5.0] %; P = .05). Twenty four-hour mortality was 9% in both groups. CONCLUSIONS: We found no evidence for improved heart rate response during bag-mask ventilation with PEEP compared with no PEEP. The PEEP valve delivered a median PEEP within the intended range. The findings do not support routine use of PEEP during resuscitation of newborns around term.