During Middle to Late Eocene hemipelagic/pelagic sediments were deposited in Dinaric foreland basin along the eastern Adriatic coast (northern margin of Neotethys, Croatia). Syn-sedimentary tectonic movements, paleogeographic position and exchanges of short-lived hyperthermal episodes affected the sedimentation and related mineral and geochemical record of these deposits. Mineral (clay) assemblage carries signature of prevailing physical weathering with significant illite and chlorite content, but climatic seasonality is suggested by smectite-interlayered phases and sporadical increase of kaolinite content. Illite crystallinity varies significantly, and the lowest crystallinity is recorded for the Lutetian samples. Illite chemistry index is always bellow 0.5 being characteristic for Fe-Mg-rich illite. The geochemical records are the most prominent (CIA up to 76, CIW up to 91) for the Istrian Lutetian (42.3-40.5 Ma), but also for Priabonian (35.8-34.3 Ma) samples of Hvar Island. The ICV values (the lowest 1.40 and the highest 10.85) of all studied samples fall above PAAS (ICV = 0.85) and point to their chemical immaturity. The Ga/Rb ratios are lower than 0.2 and K2O/Al2O3 ratios are also low (0.16–0.22), implying transition between cold and dry, and warm and humid climate, obviously trending among several warming episodes.