The paper presents ideal MHD stability calculations to show the effect of triangularity δ on the beta limit for plasmas of the NET/ITER type with ellipticity κ = 2 and aspect ratio A = 3.7. Two different types of beta optimizations have been made to clarify the influence of the equilibrium profiles. In the first set of optimizations, current profiles that are flat in the central region are prescribed and the pressure profile is optimized. The resulting pressure profiles are broad, and triangularity has only a weak influence on the beta limit. In the second set, more peaked pressure distributions are prescribed and the current profile is optimized. For peaked pressure profiles, triangularity has a clear, positive effect on the beta limit, and for δ ≥ 0.4 the peaked pressure profiles give about the same beta limit as the broad profiles. For cross-sections of small triangularity, peaking of the pressure profile is clearly unfavourable, and reasonably high beta values can be reached only if the current profile has strong gradients in the central region or if the central safety factor is significantly above unity. This is required for stability of Mercier and ballooning modes. The beta limit is found to be rather weakly dependent on the plasma current for safety factors at the plasma edge in the range of 2.2–5.