the effectiveness of neonatal hyperbilirubinaemia treatment depends directly on the amount of energy emitted by light (irradiance). this cross-sectional study aimed to determine the irradiance of phototherapy equipment in maternity wards in maceió, al, brazil. all equipment in use in the neonatal units in maceió was included in the study, totaling 36 devices, except those in maintenance. the measurement of irradiance was carried out with a radiometer. we observed that 72.20% of the equipment presented efficient irradiance and 27.76% were inefficient. the conclusion is that the majority of phototherapy devices are emitting the minimum required irradiance for neonatal jaundice treatment.