An experimental investigation is performed on turbulent boundary layers with injection and suction through a slit. The velocity profile, turbulent energy, auto-correlation function, energy spectrum, and energy balance are measured in detail, and the influence of injection and suction through a slit on the turbulent boundary layers is presented. The process of recovery to an equilibrium state from non-equilibrium state is investigated. Main results are summarized as follows. The effects of injection and suction on velocity profiles and turbulence characteristics are small in the vicinity of the wall. On the other hand, the effects of injection clearly appear in the outer layer region of the turbulent boundary layer. Convection, production, and dissipation of turbulence energy increase with injection and decrease with suction.