Objectives. To evaluate the impact of birth attendant training using the World Health Organization Essential Newborn Care (ENC) course among traditional birth attendants, with a particular emphasis on the effect of acquisition of skills on perinatal outcomes. Design. Population-based, prospective, interventional pre-post design study. Setting. 11 rural clusters in Chimaltenango, Guatemala. Population. Health care providers. Methods. This study analyzed the effect of training and implementation of the ENC health care provider training course between September 2005 and December 2006. Outcome measures. The primary outcome measure was the rate of death from all causes in the first seven days after birth in fetuses/infants ≥1500g. Secondary outcome measures were overall rate of stillbirth, rate of perinatal death, which included stillbirths plus neonatal deaths in the first seven days in fetuses/infants ≥1500g. Results. Perinatal mortality decreased from 39.5/1000 pre-ENC to 26.4 post-ENC (RR 0.72; 95%CI 0.54-0.97). This reduction was attributable almost entirely to a decrease in the stillbirth rate of 21.4/1000 pre-Essential Newborn Care to 7.9/1000 post-ENC (RR 0.40; 95%CI 0.25-0.64). Seven-day neonatal mortality did not decrease (18.3/1000 to 18.6/1000; RR 1.05; 95%CI 0.70-1.57). Conclusion. Essential Newborn Care training reduced stillbirths in a population-based controlled study with deliveries conducted almost exclusively by traditional birth attendants. Scale-up of this intervention in other settings might help assess reproducibility and sustainability. © Published . This article is a U.S. Government work and is in the public domain in the USA. Acta Obstetricia et Gynecologica Scandinavica© 2012 Nordic Federation of Societies of Obstetrics and Gynecology.