Label-free imaging techniques have recently met a lot of interest as a complement to fluorescence based imaging approaches. While imaging modalities such as second harmonic generation (SHG) and third harmonic generation (THG) microscopy allow contrast generation based on symmetry breaks in the samples, especially non-linear Raman microscopy has been pursued by many groups worldwide. The special advantage of these techniques is the possibility to generate contrast without the need for sample labelling. Instead, molecule specifi c contrast is generated based on the vibrational spectra of sample molecules. The two main approaches of this type are coherent anti-Stokes Raman scattering (CARS) microscopy and stimulated Raman scattering (SRS) microscopy. While the basic mechanism behind the two techniques is the same, the experimental setups required differ signifi cantly, mainly with respect to the detection scheme. In this contribution, I will give an overview of the state of the art for the different nonlinear Raman microscopy techniques. Different experimental approaches will be shown and their virtues will be demonstrated with examples from cell biology, material science, and biomedicine. Special emphasis will be put on the discussion of recent efforts to increase the sensitivity of non-linear Raman microscopy techniques by exploiting electronic resonances. I will demonstrate that using this approach, the detection of vibrational spectra of single molecules is within reach.