Cyanobacteria are photoautotrophic microorganisms that can be engineered to convert CO2 and water into fuels and chemicals via photosynthesis using solar energy in direct processes. Based on knowledge and progress in fermentative heterotrophic biobutanol production, cyanobacteria have been engineered to produce photosynthetic butanol from sunlight, water and CO2. This chapter discusses the present status of engineering cyanobacteria for photosynthetic isobutanol and 1-butanol production. Special focus is on recent advances in introducing enzymes and pathways, redirecting carbon toward the product, importance of five regions in the genetic constructs and optimization of the cultivation system. Also included are recent contributions addressing butanol tolerance, recovery of the produced photosynthetic butanol, life cycle assessment on environmental impacts, energy demand of photosynthetic butanol production and public acceptance of genetically engineered algae/cyanobacteria for biofuel production.