Family history of mental illness provides important information when evaluating pediatric bipolar disorder (PBD). However, such information is often challenging to gather within clinical settings. This study investigates the feasibility and utility of gathering family history information using an inexpensive method practical for outpatient settings. Families (N = 273) completed family history, rating scales, and the Mini-International Neuropsychiatric Interview (Sheehan et al., 1998) and the Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children (Kaufman et al., 1997) about youths 5–18 (median = 11) years of age presenting to an outpatient clinic. Primary caregivers completed a half-page Family Index of Risk for Mood issues (FIRM). All families completed the FIRM quickly and easily. Most (78%) reported 1+ relatives having a history of mood or substance issues (M = 3.7, SD = 3.3). A simple sum of familial mood issues discriminated cases with PBD from all other cases (area under receiver operating characteristic [AUROC] = .63, p = .006). FIRM scores were specific to youth mood disorder and not attention-deficit/hyperactivity disorder or disruptive behavior disorder. FIRM scores significantly improved the detection of PBD even controlling for rating scales. No subset of family risk items performed better than the total. Family history information showed clinically meaningful discrimination of PBD. Two different approaches to clinical interpretation showed validity in these clinically realistic data. Inexpensive and clinically practical methods of gathering family history can help to improve the detection of PBD.