Many observers have recognized and decried the disproportionate impact on young minority males of harsh sentencing policies for drug dealing. Nationwide, African-Americans and Hispanics constituted 78.2 percent of incarcerated drug offenders in 1996. This study first tested neighborhood-level explanations for racial/ethnic disproportionality. To test this family of hypotheses, a sample of State prisoners in Massachusetts was selected, and their pre-incarceration addresses were geocoded, so as to assign them to neighborhoods. The study then computed race-specific incarceration risks within groups of neighborhoods. Researchers tested alternative groups of neighborhoods meeting alternative criteria to reflect the hypotheses discussed in the literature review. Researchers then tested individual-level explanations for disparities. Overall, the data indicate that the various factors involved in the war on drugs, as implemented through harsh sentencing laws, make the war on drugs a war on those racial/ethnic groups that are the most disadvantaged in our society. This reality must be taken into account by the makers of sentencing policy. 7 tables, 40 notes, and 55 references