The dynamics of nanostructured surface phases on SrTiO(3)(001) have been analysed using in situ scanning tunnelling microscopy (STM) above 800 degrees C. During high-temperature annealing, the formation, growth and ordering of the nanostructures has been observed. Dilines, with a width of approximately 1 nm, are formed from a TiO(2)-rich intermediary at 800 degrees C. STM during annealing at 825 degrees C has enabled us to follow both the growth and dissolution of dilines. Following extended annealing, trilines with a width of approximately 2 nm and ordered two-dimensional (2D) nano-arrays form from the diline domains. Our observations of diline dissolution implies random nucleation and growth, followed by rearrangement at elevated temperature to form domains