Fetal alcohol syndrome (FAS) is currently recognized as the most common known cause of mental retardation, affecting from 1 to 7 per 1000 live-born infants. Individuals with FAS suffer from changes in brain structure, cognitive impairments, and behavior problems. Researchers investigating neuropsychological functioning have identified deficits in learning, memory, executive functioning, hyperactivity, impulsivity, and poor communication and social skills in individuals with FAS and fetal alcohol effects (FAE). Investigators using autopsy and brain imaging methods have identified microcephaly and structural abnormalities in various regions of the brain (including the basal ganglia, corpus callosum, cerebellum, and hippocampus) that may account for the neuropsychological deficits. Results of studies using newer brain imaging and analytic techniques have indicated specific alterations (i.e., displacements in the corpus callosum, increased gray matter density in the perisylvian regions, altered gray matter asymmetry, and disproportionate reductions in the frontal lobes) in the brains of individuals prenatally exposed to alcohol, and their relations with brain function. Future research, including using animal models, could help inform our knowledge of brain-behavior relations in the context of prenatal alcohol exposure, and assist with early identification and intervention.