Phraseological units, traditionally described by means of different properties, such as idiomaticity, fixedness and non-compositionality, are also subject to variation. Far from coming into conflict with the key phraseological characteristic (fixedness), variation reinforces its identity through various categories consistent across different phraseological types, different registers and different languages. This paper sets out to find a definition of phraseological variation and to establish a general framework of this phenomenon. We distinguish two main categories: variants and modifications and Ilustrate them with German, English and Spanish examples.