One of the critical issues in designing and fabricating a high performance planar solid oxide fuel cell (SOFC) stack is the development of the appropriate materials and techniques for hermetically sealing the metal and ceramic components. In the last few years significant progress has been made in the development of glass-ceramic seals for these devices. However there are still a number of areas that are in need of development. Details of glass-ceramic seal limitations and the current status of their development will be presented.