The geomorphologic and sediment transport characteristics of the middle reach of the Bah¿a Blanca estuary (Argentina) are presented. A large intertidal sedimentary structure divides the curved-funnel-shaped reach into the Main channel, which includes the waterway, and the Vieja channel. The right margin of the study are is bordered by a low marsh/tidal flat complex. Sedimentological and low-penetration seismic data show that the area is formed mostly by relict sediments of Pleistocene and Pliocene ages. Present-day deposits are very thin and are concentrated on the left platform between the navigation route and the intertidal structure. Comparison of detailed bathymetric surveys separated by 6.75 years resulted in a net erosion for all the area of 2.4¿106 m3. Assuming that the volume of sediments dredged from the navigation channel (510,000 m3 in 6 years) was originated on the erosional sectors of the study area, approximately 250,000 m3/yr are still exported from the reach. Net accumulation (up to 2 m) is concentrated on the left margin, while erosional zones (up to 4.5 m) are located on the right margin of the Main channel and the middle portion of Vieja channel. Sediment transport calculations from 15 current meter stations distributed in the area indicate a net bed load transport of sand-sized material directed towards the mouth of the estuary. The results suggest that dynamically, the middle reach of the Bah¿a Blanca estuary does not behave as a meander as was expected from its general shape. Although a preliminary estimation may indicate that the dredged sediment may proceed from the right margin, the general circulation of the estuary indicates that all reaches interchange sediments with their adjacent sectors. Sediments deposited in then middle reach are coming from the erosional processes acting in the inner reach and on the flanks of tidal flat channels.