In silico modeling of genome-scale networks offers a promising method for globally interrogating the metabolism of Clostridium beijerinckii, a microorganism of industrial interest for butanol production. The iCM926 model accurately simulates physiological behavior and provides insight into the underlying mechanisms of microbial butanol production. The model will be instrumental in efforts to better understand, and metabolically engineer, this microorganism for improved butanol production. The construction of iCM926 for a lesser-characterized microorganism highlighted important areas of investigation, e.g., genome annotations and objective functions, for future model-building efforts. This is an abstract of a paper presented at the 2011 AIChE Annual Meeting (Minneapolis, MN 10/16-21/2011).