This study presents sedimentological, palaeontological, geochemical, mineralogical and organic petrography data from a 30 m deep core representing a Mid- to Late Holocene lagoonal depositional environment, of a coastal area of Amvrakikos Gulf, Western Greece. Three horizons were dated using 14C, while the sedimentological, palaeontological and geochemical interpretations of the lagoonal sediments reveal three major lithological units deposited between around 5200 to 1600 yrs BP. The upper lithological unit extended down to a depth of 11.20 m, the middle from 11.20-21.30 m and the lower one from 21.30-30.00 m. A mean rate of sedimentation of 5.7 mm/y and a maximum rate of 12.6 mm/y were estimated. The mineralogical analysis and the magnetic susceptibility of the core points to a constant sediment - source supply. The Mid- to Late Holocene depositional environments results mainly of the inundating of the braid plain of Arachthos and secondary by Louros River. The reconstruction of the depositional environments corresponds to a shallow marine and deltaic brackish lagoon and specifically to an environment proximal to river supply. The high rates of sedimentation, as well as the interpretation of depositional environments indicate that the coastal sedimentological processes during the Mid- to Late Holocene, were mainly controlled by the progradation of rivers deltas. Moreover, the geochemical proxies, the recovered molluscs and the microfauna, as well as the organic petrography analyses indicate periods of dysoxic and hypoxic conditions prevalence. These Holocene dysoxic and hypoxic events indicate that the recent dystrophic crises in the Amvrakikos gulf are not only the result of human activities but also the contribution of natural processes.