© 2020, Gazi Universitesi. All rights reserved.Alumina (α-Al2O3) and hydroxyapatite (HA, Ca10(PO4)6(OH)2) are well-known for being clinically successful bioceramic materials. In this work, in-vitro biological characterization of the sol-gel alumina-bovine hydroxyapatite composite powders was realized. Alumina powders were synthesized through the sol-gel process. First, boehmite (AlOOH) sol was prepared utilizing aluminium isopropoxide (Al(OC3H7)3, AIP) as the starting precursor. Bovine hydroxyapatite (BHA) powders, which can be defined as naturally derived calcium phosphate powders were added as 10, 20, 30, and 50% wt. of AIP to each AlOOH sol. Homogeneous dispersion of the BHA powders in the AlOOH sol was managed due to employing Na-alginate as a kind of thickener. Gelation of the AlOOH-BHA mixtures was carried out at 110 ºC for 3h. After drying, AlOOH-BHA mixtures were heat-treated at 1300 ºC for 2h. Chemical, microstructural, thermal, and physical properties of the precursors/process products were characterized with X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Fluorescence Spectroscopy (XRF), Differential Thermal Analysis (DTA), and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) analyses. Indirect MTT assay was done to evaluate the biocompatibility of the Al2O3-BHA based biocomposite extracts using the L929 cell line. It is found that all Al2O3-BHA composite extracts with varying doses of 25% and 50% had no negative effect on the cell viability. In addition, % cell viability decreased with the increasing of the extract concentration. It can be concluded that the prepared Al2O3-BHA composites can be a good candidate for biomedical applications.