Phototherapy for jaundice in preterm infants should always be administered in accordance with specific guidelines. However, guidelines on phototherapy in very preterm and moderately preterm infants are currently lacking in France. We performed a nationwide quality improvement study of the management of jaundice in these preterm infants and compared the results with the international guidelines. Of the 275 maternity units initially contacted, 165 (60.0%) replied. Our results showed that clinical practice differs markedly from one unit to another – notably with regard to the prescription, administration, and monitoring of phototherapy and the reference curves used. Even though there is limited evidence on the safety and efficacy of phototherapy in very or moderately preterm infants, a French expert committee should be encouraged to develop consensus guidelines and thus improve quality of care in this setting.