The results of simultaneous measurements of electrical resistance, stress and strain of Ti-Ni alloys at thermocycling and during the isothermal deformation are presented. It is shown that noticeable part of strain recovery in heating takes place before the start of the reverse transformation and is connected with twinning. The isothermal loading initiates the B2→B19' and R→B19' transformations and produce almost no effect on the B2→R transformation. The results of differential thermal analysis during mechanical testing reveal that a stress may be responsible for the variation of the latent heat of the transformation.