This volume contains the papers selected for presentationat IPCO VI, the Sixth InternationalConferenceonInteger ProgrammingandCombinatorialOptimi- tion, held inHouston, Texas, USA, June22{24,1998.TheIPCOseriesofconf- ences highlights recent developments in theory, computation, and applications of integer programming and combinatorial optimization. These conferences are sponsoredby the Mathematical ProgrammingSociety, and are held in the years in which no International Symosium on Mathema- cal Programming takes place. Earlier IPCO conferences were held in Waterloo (Canada) in May 1990;...