Carbon nanotubes have exciting potential to provide high performance materials of the future. One of the main challenges is assembling the billions of miles of individual nanotubes in each pound of product nanotube fiber or sheet in such a way that the properties of the individual nanotubes are most effectively utilized. In this study a novel wet fiber spinning method was developed in which carbon nanotubes dispersed in a surfactant are injected into a rotating acid bath which coagulates the dispersion to form a macroscopic fiber. This flocculation method produces highly conducting carbon nanotube fibers and sheets without the need for a polymer binder. The mechanical strength is sufficient for several applications and can be improved by either heat treatment or by incorporation of a polymer in the yarn, and subsequent draw. Poly(Vinyl Alcohol) (PVA)-treated fibers yield outstanding mechanical properties and a toughness that is comparable to spider silk. Other polymers, such as polyvinylpyrrolidone (PVP) also enhance mechanical properties. Inorganic additives, such as platinum, can be incorporated into the fiber matrix to provide multifunctionality.