IMPORTANCE: Multifactorial dyslipidemia, characterized by elevated total cholesterol (TC) or low-density lipoprotein cholesterol (LDL-C), is associated with dyslipidemia and markers of atherosclerosis in young adulthood. Screening for dyslipidemia in childhood could delay or reduce cardiovascular events in adulthood. OBJECTIVE: To systematically review the evidence on benefits and harms of screening adolescents and children for multifactorial dyslipidemia for the US Preventive Services Task Force (USPSTF). DATA SOURCES: MEDLINE, Cochrane Central Register of Controlled Trials, and PubMed were searched for studies published between January 1, 2005, and June 2, 2015; studies included in a previous USPSTF evidence report and reference lists of relevant studies and ongoing trials were also searched. Surveillance was conducted through April 9, 2016. STUDY SELECTION: Fair- and good-quality studies in English with participants 0 to 20 years of age. DATA EXTRACTION AND SYNTHESIS: Two investigators independently reviewed abstracts and full-text articles and extracted data into evidence tables. Results were qualitatively summarized. MAIN OUTCOMES AND MEASURES: Outcomes included dyslipidemia (TC≥200 mg/dL or LDL-C≥130 mg/dL) and atherosclerosis in childhood; myocardial infarction and ischemic stroke in adulthood; diagnostic yield (number of confirmed cases per children screened); and harms of screening or treatment. Simulated diagnostic yield was calculated as initial screening yield × positive predictive value from a study with confirmatory testing. RESULTS: Screening of children for multifactorial dyslipidemia has not been evaluated in randomized clinical trials. Based on 1 observational study (n = 6500) and nationally representative prevalence estimates, the simulated diagnostic yield of screening for elevated TC varies between 4.8% and 12.3% (higher in obese children [12.3%] and at the ages when TC naturally peaks-7.2% at age 9-11 years and 7.2% at age 16-19 years). One good-quality randomized clinical trial (n = 663) found a modest effect of intensive dietary counseling for a low-fat, low-cholesterol diet on lipid levels at 1 year in children aged 8 to 10 years with mild to moderate dyslipidemia; mean between-group difference in TC change from baseline was -6.1 mg/dL (95% CI, -9.1 to -3.2 mg/dL; P < .001). Between-group differences dissipated by year 5. The intervention did not adversely affect nutritional status, growth, or development over the 18-year study period. One observational study (n = 9245) found that TC concentration at age 12 to 39 years was not associated with death before age 55 years. CONCLUSIONS AND RELEVANCE: The diagnostic yield of lipid screening varies by age and body mass index. No direct evidence was identified for benefits or harms of childhood screening or treatment on outcomes in adulthood. Intensive dietary interventions may be safe, with modest short-term benefit of uncertain clinical significance.