Background Prenatal alcohol exposure (PAE) is linked to impaired performance on tests of retrospective memory, but prospective memory (PM; the ability to remember and act on delayed intentions) has not been examined in alcohol-exposed children. We investigated event-based PM in children with heavy PAE and the degree to which associations between PAE and PM are influenced by IQ, executive functioning (EF), retrospective memory, and attention deficit/hyperactivity disorder (ADHD). Methods We administered a computerized PM task to 89 children (Mage = 11.1 years) whose mothers were recruited prenatally: 29 with fetal alcohol syndrome (FAS) or partial FAS (PFAS), 32 nonsyndromal heavily exposed (HE), and 28 Controls. We examined effects of diagnostic group, cue focality, and task difficulty on PM performance. The association between a continuous measure of alcohol exposure and PM performance was also examined after controlling for sociodemographic confounders. Mediation of alcohol effects on PM by IQ, EF, and retrospective memory scores was assessed as was the effect of ADHD on PM performance. Results Children with FAS/PFAS made more PM errors than either HE or Control children. PAE was negatively related to PM performance even after adjusting for sociodemographic confounders, EF, and retrospective memory. This relation was only partially mediated by IQ. PAE was related to ADHD, but ADHD was not related to PM performance. Conclusions Fetal alcohol-related impairment in event-based PM was seen in children with FAS/PFAS. The effect of PAE on PM was not attributable to impaired EF and retrospective memory and was not solely attributable to lower IQ. Consistent with previous studies, we found no effect of ADHD on event-based PM performance at this age. This is the first study documenting PM impairment in children with heavy PAE and identifies a new domain of impairment warranting attention in diagnosis and management of fetal alcohol spectrum disorders.