High-resolution reflection seismic profiles and core analyses of sedimentary sequence near the Sea of Marmara (SoM) entrance to the Strait of İstanbul (SoI, Bosphorus) provide detailed record of sealevel changes since the Late Glacial Maximum (LGM). The sequence is deposited over the LGM erosional surface at a maximum depth of -105 m. It includes seven seismic units that can be confidently correlated with $^{14}C$-dated (uncalibrated) sedimentary units in the cores. Unit-S1f consists of conformable beds constituting a ridge-like future in the middle of the main channel and dipping in opposite directions. We interpret this unit as a levee deposited in the main paleo-strait’s channel. The lowermost 175 cm part of Core MD-2750 represents the upper part of the levee deposit (Unit-S1f), which comprises silty and sandy beds with marine molluscan shells. This unit is differentiated from the overlaying other units by its relatively coarse-grained nature. Unit-S1f represents levee deposits of the paleo-SoI channel that was deposited by a Black Sea outflow during 12000-10 600 yr BP. The levee unit is overlaid by Unit-S1e over ersoional surface E, which corresponds to the onset of the early Holocene Sapropel (Çağatay et al., 2000) as indicated by high Corg values (>1.5 wt%) and its stratigraphic position in Core MD-2750. This sapropelic layer was previously dated 10 600-6400 yr BP by Çağatay et al. (2000). Its onset age is consistent with the 14C ages of 10 950 yr BP and 10 450 yr BP obtained below and above truncation surface E, therefore, age of the reflector E can be estimated as 10 600 yr BP. The reflection surfaces at the base of Unit-S1d and S1c correspond to wave-cut terraces at -71 and -63 m, respectively, and are estimated to be 10 600 and 9800 yr BP. The seismic Unit-S1b comprises deltaic sediments that were deposited during 6400-3200 yr BP. Isopach map and forset directions of the deltaic unit indicate that the delta was sourced from Kurbağalıdere River. Contrary to the interpretations of Hiscott et al. (2002) and Gökaşan et al. (2005) that this deposit formed during the course of a rapid sealevel rise, our dating places its growth after sealevel had nearly reached its modern level about 6500 yr BP. As mapped out in plan view the outline of the topsets and foresets of Unit-S1b coincides well with the same deposit mapped by Gökaşan et al. (2005). We propose the following sequence of events leading to the delta formation. According to global sealevel curves (e.g. Fairbanks, 1989), the rate of sealevel rise decreased after 6500 yr BP. This decrease combined with an increase in sediment supply during mid-Holocene climatic optimum resulted in the deltaic progradational sedimentation on the shelf of southern enterance of SoM to SoI. This conclusion is in agreement with the fact that the mid Holocene is a well known period for widespread delta development (Stanley and Hait, 2000). The change from the progradational stage to the aggradational stage of delta development at 4700 yr BP is marked by a relatively rapid rise of sealevel as indicated by climbing delta foreset-topset transition. The onset of aggradational period also coincides with establishment of the present dualflow regime (Çağatay et al., 2000) with the Mediterranean under-current in the SoI, forming a northward sediment drift. The delta deposition was terminated when increased base level due to further global sealevel rise combined with a probable decrease in sediment input by the Kurbağalıdere River at 3200 yr BP. This date is supported by the correlation with the age of the late Holocene Sapropel layer and by a $^{14}C$ age of 4400 yr BP in Core TSU03-13 below the eroded uppermost topsett bed. The Kurbagalıdere River, with a present day annual water and sediment discharges of 80 m3 and 60 000 tons (EİE, 1993) draining a 180 m high ground southeast of the SoI, is large enough to form such a delta having about 290 x 106 tons of sediment. In this study, we present detailed seismic stratigraphic analysis of high resolution shallow seismic lines crossing an area near the southern entrance of SoI, together with the core stratigraphy. Our main objectives are to discuss the chronostratigraphic evolution of the Holocene sediments including delta formation in the paleo-SoI channel, and shed light on the water exchange problem between the Marmara and the Black Seas during the Holocene (last 12 000 years).