Four hypotheses concerning the character and consequences of participation in an ethnic enclave economy are examined. The first concerns the justifiability of operationalizing enclave participation on the basis of place of residence, as done in recently published research. The second and third pertain to the effects of ethnic economy participation on entrepreneurs and workers, respectively. The fourth deals with determinants of self-employment among ethnic minorities. Two data sets are employed in this analysis: the 1980 Census individual sample for Cuban-born adult immigrants in South Florida and a 1983-86 longitudinal survey of Mariel entrants in the same area. These two independent data sets permit a more authoritative evaluation of the hypotheses. They also allow an assessment of the extent to which earlier findings about the pre-1980 Cuban-born population apply to the more recent entrants. Results consistently contradict depictions of ethnic enterprise as vehicles for exploitation and of enclaves as mere residential agglomerations. These structures are defined by physical proximity of firms, not dwellings. Ascriptive factors--primarily gender and marital status--play a decisive role in the emergence of enclave enterprise net of human capital endowments. Theoretical implications of these findings, in particular the relationship between intact nuclear families and the rise of an entrepreneurial minority, are discussed.