Previous research has shown a relationship between prenatal teratogenic exposure and impaired cognitive functioning. However, data regarding the long-term outcome of prenatal teratogenic exposure are minimal. The present study investigated the long-term neuropsychological functioning (specifically attention and memory) of adults prenatally exposed to alcohol or phenylalanine, and examined whether there was evidence to suggest that there are effects specific to individual teratogens. Using a battery of attention and memory measures the performance of 17 adults diagnosed with Fetal Alcohol Syndrome (FAS) and 13 adults with Maternal Phenylketonuria Syndrome (MPKUS) was assessed. In order to identify the pattern of deficits associated with prenatal teratogenic exposure, an age and CA and IQ matched control group was assessed. Attention was broadly assessed using Mirsky et al.'s (1991) neuropsychological model of attention. The memory and learning tests administered included a number of well standardized measures of verbal learning, verbal and visual recall, delayed recall, and recognition. Paired comparisons between the FAS group and age and CA and IQ matched controls indicated a unique pattern of attention and memory deficits consistent with previous research with children and adolescents. Specifically, adult individuals with FAS appear to have deficits in acquisition of new material, delayed recall of verbal material and in response inhibition. Paired comparisons between the MPKUS group and CA and IQ matched controls indicated that the pattern of attention and memory deficits seen in adults with MPKUS is difficult to distinguish when the effect of IQ is removed. A randomized block design using IQ as the blocking variable and group (FAS, MPKUS, or Controls) as the treatment variable was utilized to examine the question of whether the two prenatal teratogen groups differ from one another and from Controls in terms of attention and memory ability. Ten blocks of three participants (FAS, MPKUS and Control) matched on IQ were formed. The randomized block analyses revealed few differences between the groups and failed to reveal a number of the differences found in the paired comparisons between the prenatal teratogen groups and the CA and IQ matched Control group. Possible reasons for these differences are discussed.