Recent research argues that among former New World colonies a nation’s past dependence on slave labor was important for its subsequent economic development (Engerman and Sokoloff, 1997, 2002). It is argued that specialization in plantation agriculture, with its use of slave labor, caused economic inequality, which concentrated power in the hands of a small elite, adversely affecting the development of domestic institutions needed for sustained economic growth. I test for these relationships looking across former New World economies and across states and counties within the U.S. The data shows that slave use is negatively correlated with subsequent economic development. However, there is no evidence that this relationship is driven by large scale plantation slavery, or that the relationship works through slavery’s effect on economic inequality.