There is conflicting evidence as to whether phototherapy given to jaundiced newborns may have a carcinogenic effect. Previously, in a large Northern California cohort, phototherapy was associated with increased risk of non-lymphocytic leukemia (although this did not remain significant after controlling for confounding). A recent study from Quebec suggested phototherapy could increase the risk of solid tumors, but only after a latent period of several years. This study re-assessed the relationship between newborn phototherapy and childhood cancer in the Northern California cohort with more children and increased follow-up time and sought to confirm a late increase in solid tumors reported from Quebec. We found no evidence for increased risk of any type of cancer following exposure to neonatal phototherapy, whether or not we included a latent period in analyses.