Karstic environments provide a large range of rock-shelters and cave-nets and have always been „goldmines‟ for archaeologists, since they allow a better conservation of remains. Therefore, the first investigations conducted in East Kalimantan by Franco-Indonesian teams have focused on the numerous and impressive karst ranges and outcrops. More than 150 caves and rock-shelters have been surveyed since 1992 in the East Kutai district only, including 36 ornate caves containing a very specific rock art expression. Archaeological excavations, since 2003 in cooperation with central and local Indonesian authorities, have provided important insights into human history from the past (from 12,500 YBP) until the proto-contemporary periods, in a large triangular area (Sangkulirang-Bengalone-Merapun). After seven years of investigations in the deserted area of GunungMarang, our project has moved 50km northwest towards the Merabu district (south of Berau Province), where large karstic outcrops and a complex rock art expression are present. In addition, Lebbo' local communities are still occupying these remote territories, with a relatively traditional way of life. Excavations conducted in Liang Abu, since 2009, have been an exceptional opportunity to combine complementary approaches, including ethno-historical, ethno-linguistic, archaeological (ceramic, lithic, archaeozoology) and genetic investigations. This aims to explore genetic and cultural links between Lebbo‟ communities and their living neighbours, their putative ancestors buried or deposited in caves and rock cracks and broader issues related to the settlement processes, origin and dispersal of the Lebbo‟ communities linked to karstic environment.