Abstract A brief account of the structure and dynamics of freely propagating premixed gas flames in the regime of spontaneous flame instability is given. Recent theoretical studies providing a reduction of the pertinent free-boundary problem to a single evolution equation for the flame interface are discussed. The striking feature of the premixed flame is described. The flame, being an entirely deterministic system, proves capable of displaying irregular spatio-temporal behaviour similar to that known in hydrodynamic turbulence.