The beta limit for stability against MHD modes is calculated for a large aspect ratio tokamak. The results are found to be similar to those calculated numerically for small aspect ratio. For ideal modes, the beta limit is found to be proportional to current, having the form (28/qa)% (or 5.6 I (MA)/a(m) B(T)), with a maximum value of 14% at qa = 2, being the inverse aspect ratio. A limit of 7% is found when tearing-mode stability is also required.