Laser damage in KDP crystals has been studied since several years and more accurately with emergence of projects like LMJ (Laser MÃ©gaJoule, in France) or NIF (National Ignition Facility, in US). Laser damage tests are essentially performed at 351-nm wavelength (3ω), with regards to their optical behaviours on forementioned facilities. But only few data are available at 1064 nm (1ω) and at 532 nm (2ω), and even with wavelength-mixing more representative of operational conditions of KDP crystals. So in a first approach, we tried to carry out an identity chart of the crystal by performing mono-wavelength tests at 1ω, 2ω and 3ω. Then, a campaign of combination of multi-wavelength (typically 3ω and 1ω) tests has been started with several temporal delays between 3ω and 1ω pulses. These first results lead us to improve pre-existing modelling codes developed by CEA, which have proved their robustness to 3ω -experiment results. Foremost interests consist in implementing wavelength dependency and energy deposition mechanism as a consequence of our first observations on KDP.© (2009) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.