Matplotlib suptitle prints over old title

figure.suptitle returns a matplotlib.text.Text instance. You can save it and set the new title:

txt = fig.suptitle('A test title')
txt.set_text('A better title')
plt.draw() 

Resurrecting this old thread because I recently ran into this. There is a references to the Text object returned by the original setting of suptitle in figure.texts. You can use this to change the original until this is fixed in matplotlib.