The objective of this paper is to critically assess the basis of the hypothesis that the ethnicity of Hispanics is by itself a risk factor of NIDDM. Showing that the definition of the term Hispanics has both operational and methodological problems, it is argued that in the United States, a group identified by this term is genetically, as well as culturally, heterogeneous. Further, the actual risk factors of NIDDM may simply co-vary with the ethnicity of Hispanics, so that the notion that this ethnicity is a stand-alone independent risk factor of NIDDM may be too simplistic.