The aim of this Thesis is to represent geochemical characteristics of the Miocene clayey bauxites of Strmendolac including the distribution of the REE, and develop the model of bauxite genesis in comparison to geochemical characteristics of the insoluble residue of the bauxite footwall and hanging wall rocks. Four samples of the bauxite, four samples of the limestones and one sample of the marl were collected, while the three samples of the bauxite, two of the limenstones and one of the marl were thoroughly analysed. Mineral composition of the analysed samples was determined by XRD analysis and petrographic characteristics of all the samples were specified by polarised microscopy. The chemical analyses were carried out using inductivity coupled plasma atomic emisson and mass spectrometry (ICP-AES and ICP-MS). According to their petrographic characteristics limestones were classified as biomicrites and the Upper Cretaceous age is determined on the basis of their fossil record. The bauxites are characterized by clayey or aphanitic texture. Major mineral components in the bauxites are gibbsite, kaolinite, hematite, goethite and accessory mineral anatase. The geochemical examination revealed genetic relationship of bauxite and their footwall limestones. This is proved by their similar Zr/Hf and Nb/Ta ratios, chondrite normalized trace element patterns, chondrite normalized REE patterns, ΣREE, ΣLREE/ΣHREE ratio and negative Eu anomaly. Ce anomaly is not equal for all the analysed samples. It´s concluded that the Miocene bauxites of Strmendolac, near Trilj were probably formed in situ by weathering of the limestones, while the nature of the siliciclastic material being transported by rivers to the sedimentary basin is presumed to be different during sedimentation of the limestones.