Laser intensity at focus is probably the most relevant parameter for any laser-matter interaction. Al low intensities, the direct measurement is easy. However as the intensity increases it is impossible to introduce the detector close to the focal spot. Therefore indirect measurement if the only possibility for the moment. There are new techniques that take profit of the huge intensity and the plasmas that are created to have what it is beginning to be called in-situ measurement of the intensity. Such emerging techniques are going to be presented.