This paper argues for a feature called Sonorant Voice (SV), which replaces the traditional feature [sonorant]. It is underlyingly present in all sonorants and in obstruents that function as sonorants within a system. This feature differs from [sonorant] in several ways: (a) it defines the type of voicing present in sonorants, (b) it can be present in obstruents, and (c) it bears a special relationship to the feature Nasal in that a nasal consonant is the unmarked realization of a consonant with the feature SV. Two major kinds of evidence are given for SV. First, alternations between voiced stops and nasals in some languages suggest that the two are allophones (e.g. Southern Barasano, Slave) or form a natural class (Rotokas), a relationship that is captured through the feature SV. Second, cases in which voicing and a nasal surface in the same environment (e.g. Navajo, Irish) can be accounted for by the use of SV.