Volume 10 in the Trends in Functional Programming (TFP) series presents some of the latest research results in the implementation of functional programming languages and the practice of functional programming. It contains a peer-reviewed selection of the best articles presented at the 2009 Tenth Symposium on Trends in Functional Programming held in Komárno, Slovakia. TFP 2009 was co-located with the Third Central European Functional Programming School (CEFP 2009) and organized by the Department of Programming Languages and Compilers, Faculty of Informatics, Eötvös Loránd University, Budapest and the Selye János University, Komárno.