Sawtooth oscillations are a common phenomenon in standard tokamak discharges. Although favourable in a reactor for Helium ash removal, large sawtooth crashes are known to provide seed islands for neo-classical tearing modes. For JET, a database has been set up to analyse a general scaling of sawtooth properties in order to predict sawtooth behaviour in ITER. The effect of plasma shaping on the sawtooth stability is analysed in more detail. Elongation and triangularity are predicted to affect the internal kink stability [1,2] and recent results showed that plasma shaping altered the sawtooth behaviour in the TCV tokamak [2,3]. Dedicated experiments have been carried out in JET to study these effects.