Gradient elution is a powerful tool for complex mixtures when isocratic methods fail to separate sufficiently. Gradient elution has become a well accepted technique for routine analysis due to the need to separate more and more complex samples and since more reliable gradient instrumentation are now available. However, it is sometimes not simple to develop and transfer gradient methods. This topic covers the basics of gradient elution related to the different LC techniques (RP, NP, IEC), describes the factors to consider when developing a gradient method and the recent advances in the theory and practice.