ThisvolumecontainstheproceedingsoftheFifthInternationalSymposiumon FunctionalandLogicProgramming, FLOPS2001, heldinTokyo, Japan, March 7{9,2001, andhostedbyWasedaUniversity. FLOPSisaforumforresearchonallissuesconcerningfunctionalprogr- ming and logic programming. In particular, it aims to stimulate the cro- fertilizationaswellastheintegrationofthetwoparadigms. ThepreviousFLOPS meetingstookplaceinFuji-Susono(1995), Shonan(1996), Kyoto(1998), and Tsukuba (1999). The proceedings of FLOPS'99 were published by Springer- VerlagasLectureNotesinComputerScience, volume1722. There were 40 submissions, 38 of which were considered by the program 1 / committee. TheycamefromAustralia(5), Belgium( ), Denmark(3), Egypt 3 1 1 2 1 / / / / (1), France( ), Germany(2 ), Italy(4 ), Japan(5), Korea(1 ), Mexico 2 3 3 2 1 1 5 / / / (1), TheNetherlands(1 ), Spain(10 ), Switzerland(1), UK(1 ), andUSA 6 6 6 1 / (1 ). Eachpaperwasreviewedbyatleastthree, andmostlyfour, reviewers. 2 Theprogramcommitteemeetingwasconductedelectronicallyfortheperiodof twoweeksinNovember2000. Asaresultofactivediscussions,21papers(52. 5%) wereselectedforpresentation, whichappearinthisvolume. Inaddition, weare verypleasedtoincludeinthisvolumefullpapersbythreedistinguishedinvited speakers, namelyGopalanNadathur, GeorgeNecula, andTaisukeSato. Onbehalfoftheprogramcommittee, theprogramchairswouldliketothank theinvitedspeakerswhoagreedtogivetalksandcontributepapers, allthosewho submittedpapers, andalltherefereesfortheircarefulworkinthereviewingand selectionprocess. Thesupportofoursponsorsisalsogratefullyacknowledged. Inparticular, wewouldliketothanktheJapanSocietyforSoftwareScience andTechnology(JSSST), SpecialInterestGrouponPrinciplesofProgramming, andtheAssociationforLogicProgramming(ALP). Finally, wewouldliketo thankthemembersoftheorganizingcommittee, notablyZhenjiangHu, Yasuhiro Ajiro, Kazuhiko Kakehi, and Madoka Kuniyasu, for their invaluable support throughoutthepreparationandorganizationofthesymposium. January2001 HerbertKuchen KazunoriUeda Symposium Organization Program Chairs Herbert Kuchen University of Munster, ] Germany Kazunori Ueda Waseda University, Tokyo, Japan Program Committee Sergio Antoy Portland State University, USA Gopal Gupta University of Texas at Dallas, USA Michael Hanus University of Kiel, Germany Fergus Henderson University of Melbourne, Australia Zhenjiang Hu University of Tokyo, Japan Herbert Kuchen University of Munster, ] Germany Giorgio Levi University of Pisa, Italy Michael Maher Gri th University, Brisbane, Australia Dale Miller Pennsylvania State University, USA I. V. Ramakrishnan State University of New York at Stony Brook, USA Olivier Ridoux IRISA, Rennes, France Mario Rodr guez-Artalejo Complutense University, Madrid, Spain Colin Runciman University of York, UK Akihiko Takano Hitachi, Ltd.