Of all approaches to controlled thermonuclear fusion the tokamak experiments have been most successful. Over the last decade particularly three large devices have achieved plasma density,n, temperature,T, and energy confinement time,τ E, in ranges necessary for a fusion reactor plasma. Such maximum values have, however, been obtained not yet simultaneously but only in separate pulses, although the crucial triple product,nTτ E, has also been improved by several orders of magnitude. The high temperatures sufficient in a fusion reactor can be produced by injection of neutral atoms or by absorption of radio frequency waves in the ion cyclotron frequency range. The plasma confinement (τ E≈1s) is still not understood and is handled through empirical “scaling laws”. Particle densities have usually been on the low side (n≤5×1019 m−3) because increased fuelling rates can easily lead to violent current disruptions. Progress in obtaining peaked density profiles with pellet injection has led to high density plasmas without disruptions. Serious unsolved problems concern the spoiling of the fusion rates by (nonhydrogenic) impurities, the plasma parameter control over longer periods of time and indeed the plasma heating by fusion alpha-particles (“ignition, burning”). The most urgent technological question refers to the lifetime of the first wall which is in direct contact with the plasma. An important step towards ignition has been made by the recent JET/DT experiments in which, for the first time, the actual reactor fuel component tritium has been used to produce neutrons. The “next generation” tokamak ITER is, at present, being planned and designed in a world-wide collaborative effort. It should be operating before the year 2010 and is intended to investigate an ignited plasma burning for several minutes.