Global population growth is projected to outpace plant-breeding improvements in major crop yields within decades. To ensure future food security, multiple creative efforts seek to overcome limitations to crop yield. Perhaps the greatest limitation to increased crop yield is photosynthetic inefficiency, particularly in C sub(3) crop plants. Recently, great strides have been made toward crop improvement by researchers seeking to introduce the cyanobacterial CO sub(2)-concentrating mechanism (CCM) into plant chloroplasts. This strategy recognises the C sub(3) chloroplast as lacking a CCM, and being a primordial cyanobacterium at its essence. Hence the collection of solute transporters, enzymes, and physical structures that make cyanobacterial CO sub(2)-fixation so efficient are viewed as a natural source of genetic material for C sub(3) chloroplast improvement. Also we highlight recent outstanding research aimed toward the goal of introducing a cyanobacterial CCM into C sub(3) chloroplasts and consider future research directions.