This chapter discusses the distinction between natural kinds and natural properties. Some theorists deny the distinction, and claim that natural kinds can be identified with properties. For example, natural kinds might be understood as the perfectly natural properties, reducible to properties or the extensions of properties. Alternatively, one might argue that natural kinds and natural properties are distinct and that natural kinds could be considered as a sui generis type of entity. For example, one might hold that natural kinds require a distinct kind of universal, substantival universal, or sortal. Alternatively, one might claim that properties themselves form natural kind groupings, in virtue of causal mechanisms. This chapter argues that classification into natural kinds can reflect real differences between natural groups, without the supplementary ontological distinction between properties and kinds.