There is a major concern among the American people that juvenile crime is escalating out of control. Juvenile curfew laws have been the fastest growing intervention to combat youth violence and juvenile crime. A single-system experimental replication design, ABAB, was used to examine whether the Juvenile Curfew Act of 1995 is effective in reducing juvenile crime in the District of Columbia. The sample for the study was the District of Columbia (N = 1). Archival data were obtained from the Information Technology Division of the Metropolitan Police Department for the time period of October 1, 1993 to September 30, 2001 of persons arrested under age 18. The data were analyzed using statistical software, SINGWIN, designed for single-system research. A five-step procedure was used to analyze each variable of the data: (1) visual analysis of the data, (2) calculation of descriptive statistics, (3) check for autocorrelation, (4) check for a significant trend, and (5) determination of whether a two-standard-deviation-band approach (Shewart chart) and/or t-test can be used to analyze the data. The findings from this research study showed the Juvenile Curfew Act of 1995 effective in reducing part 2 (non-violent) juvenile crime arrests in Washington, D.C. The possible reasons why juvenile curfew laws are not effective in reducing all types of juvenile crime (e.g., violent crimes) or appropriate as the only method of intervention are discussed. For example, curfew laws exclude the hours when juveniles are most likely to commit crimes, they do not include the entire juvenile population, there is inconsistent enforcement of the law by police, they do not fully incorporate the theories and research related to juvenile delinquency, and they do not address the major correlates of delinquency (e.g., individual, family, peers, and school factors). Future research on juvenile curfew laws needs to be completed to ascertain why these laws are ineffective in reducing certain types of crime (e.g., violent crime) and to determine whether they can be made more effective. Until such research is conducted, curfew laws may continue to be a popular but seemingly ineffective intervention when used alone in the fight against youth violence and juvenile crime.