Soft β limiting phenomena have been observed in T-10 in ECRH heatedplasmas. Neoclassical tearing modes are supposed to be responsible for the βlimitation. MHD onset was observed at high βp values but low βN values.The critical β has been found to be almost independent of the collisionality parameterνe*. Sawtooth stabilization by ECCD does not result in an increase of criticalbeta. A dependence of the critical β on the q(r) profile (modified by ECCD)has been observed.