Magnetic resonance imaging (MRI) and functional MRI studies involving n-back spatial working memory (WM) tasks were conducted in adults and children with Fetal Alcohol Spectrum Disorders (FASD), and in age- and sex-matched controls. FMRI experiments demonstrated consistent activations in regions of the brain associated with working memory. Children with FASD displayed greater inferior-middle frontal lobe activity, while greater superior frontal and parietal lobe activity was observed in controls. Control children also showed an overall increase in frontal lobe activity with increasing task difficulty, while children with FASD showed decreased activity. FASD adults demonstrated less functional brain activity overall, but greater inferior-middle frontal lobe activity during the simpler tasks, relative to controls. Control adults demonstrated greater inferior frontal activity with increasing task difficulty, while this pattern was not consistently observed in FASD adults. All four groups showed increasing activity with increases in task difficulty in the parietal and frontal regions at more superior slice levels. The results suggest impairment in spatial working memory in those with FASD that does not improve with age, and that fMRI may be useful in evaluation of brain function in these individuals.