A tissue resecting instrument includes a housing, a shaft rotatable relative to the housing and defining a proximal end portion disposed within the housing and a distal end portion distally-spaced from the housing, a cutting member operably associated with the distal end portion of the shaft, a turbine disposed within the housing and operably associated with the proximal end portion of the shaft, and a fluid outflow tube operably associated with the housing. The fluid outflow tube is adapted to connect to a suction source to enable the suctioning of fluid and resected tissue proximally through a lumen of the shaft, an interior of the housing, and into the fluid outflow tube. The turbine is configured such that proximal fluid flow across the plurality of fins of the turbine urges the turbine to rotate, thereby rotating the shaft relative to the housing to enable tissue resection with the cutting member.
