Practical applications of HTS tapes cannot avoid various stresses and strains, including tension, bending and/or torsion. These loads directly affect the critical current and AC losses of HTS tapes. Thus the investigation of the effect of stress/strain on HTS tapes is important for practical applications. Here, the critical cur- rents and AC losses are measured at 77 K for different Bi2223/Ag composite tapes under different room temperature stress/strain. The strain dependence of the critical currents and AC losses of Bi2223/Ag composite superconducting tapes are studied. A comparison is given for the measured results and the values calculated from the formulae developed from the Norris formula and critical current-strain relationship. [ABSTRACT FROM AUTHOR]