A robust indirect adaptive controller under additive and parametric disturbances is introduced in this paper. The orders and time delay of the plant are assumed to be unknown apart from their known upper bounds. It is also assumed that a robust linear controller of the plant can be defined for known parameters, model orders and time delay. The robust adaptive controller switches between model structures depending on an overall criterion of performance. It is not only proved that the adaptive control scheme is stable but that its asymptotic performance can be set arbitrarily near to the performance achievable for a known plant. Finally, a simulation illustrates the performance of the scheme.