Dark fermentation of biomass using mixed bacterial cultures is one approach to producing renewable H-2. The objective of this work was to determine if this approach could be applied to N-deficient feedstocks using an N-2-fixing mixed culture. A mixed culture produced up to 240 mL H-2/g glucose (1.9 mol H-2/mol glucose) from a medium initially lacking combined N. Yields from sugarcane were also promising: 170 mL H-2/g volatile solids (7.5 mmol H-2/g volatile solids). This approach could reduce economic and environmental costs of fermentative H-2 production, provide combined N for subsequent bioconversion stages, and improve effluent suitability for subsequent uses.