Time-domain representation of the original Smith predictor is presented for systems with feedback delay. Sensitivity to parameter uncertainties is analyzed for a marginally stable, for an asymptotically stable and for an unstable second-order plant. A series of stability diagrams are constructed using the D-subdivision method and Stepan’s formulas. Transition to the stability diagrams subjected to delayed state feedback is established. It is demonstrated that the Smith predictor is sensitive to infinitesimal parameter mismatches for the marginally stable plant. It is shown that the Smith predictor can stabilize unstable plants for some extremely detuned internal model parameters.