Five roAp stars for which accurate fundamental parameters have been determined based on interferometric data are overplotted on the roAp star theoretical instability strip derived by Cunha (2002). The 1σ-error box (log (T_eff), log (L/L_⊙)) and the 1σ radius limits are shown for HD 24712. The other four stars are, in order of increasing luminosity, α Cir, γ Equ, 10 Aql, and β CrB. Small open circles show models where high radial order pulsations were found to be excited. The numbers next to each open circle indicate the characteristic frequency in mHz excited in the corresponding model.