Objective: To test the hypothesis that patients with pediatric bipolar disorder (PBPD) would demonstrate impairment relative to diagnosis-free controls of comparable age, gender, and IQ on measures of memory functioning. Method: The authors administered a battery of verbal and visuospatial memory tests to 35 outpatients with PBPD and 20 healthy controls who participated as volunteers in this study. Groups did not differ on age, gender, or IQ. Results: Consistent with findings in adults with BPD, patients with PBPD performed more poorly than controls on measures of verbal learning/memory and delayed facial recognition memory. Impaired memory was particularly evident in patients with comorbid PBPD/attention-deficit/hyperactivity disorder or acute mood symptoms. Conclusions: These findings suggest that deficits in verbal learning and memory, as well as some aspects of visuospatial memory, characterize patients with narrow phenotype PBPD. Further research is needed, however, to clarify the roles of comorbid attention-deficit/hyperactivity disorder and acute mood state in the emergence of these deficits. Given the apparent continuity in memory dysfunction between adult BPD and narrow phenotype PBPD, research aimed at elucidating underlying neural mechanisms for this set of deficits is warranted. J. Am. Acad. Child Adolesc. Psychiatry, 2005;44(5):461-469. Key Words: memory, bipolar disorder.