During the years 1994--2000 the HERA ep collider has been running with electrons and positrons at center-of-mass energies \sqrt {s}=300--320 GeV. The reaction ep\to eX is sensitive to new physics at mass scales in the TeV range. Contact interaction analyses of the data at high momentum transfer Q²=200--50000 GeV² performed by the H1 and ZEUS collaborations are presented here, investigating compositeness models, leptoquarks, quarks of finite size and large extra dimensions.

PACS numbers: 13.60.Hb, 13.90.+i