Polyindole stabilized silver cobalt oxide (Pind/Ag-Co3O4) nanocomposites were synthesized, characterized and evaluated for their antibacterial and antifungal activities. Polyindole, cobalt oxide and Pind/Ag-Co3O4 were prepared by chemical oxidative polymerization, co-precipitation and reflux condensation method, respectively. Colloidal nanoparticles of polyindole, cobalt oxide and nanocomposite were characterized by Fourier transform infrared spectrophotometer (FT-IR), X-ray diffraction pattern (XRD), scanning electron microscope with energy dispersive X-ray diffraction study (SEM-EDAX) and high resolution transmission electron microscope with selected area diffraction (HRTEM-SAED). FTIR spectra revealed the functional group's transformation of cobalt oxide nanoparticles. The crystalline nature of the samples was confirmed by XRD study. The SEM images revealed the various shapes and surface morphology of the nanocomposites. Further, the elemental composition was confirmed by EDAX. The HRTEM images showed shapes such as spherical, cylindrical, rectangular, rods, oval and square. The average particle size of the nanocomposites found to be similar to 20 nm which is in good agreement with XRD analysis in terms of the size of the crystalline. The Pind/Ag-Co3O4 nanocomposites exhibited improved antibacterial and antifungal activities against pathogenic bacteria and fungi. Hence, these nanocomposites could be used as a potential candidate for the biomedical applications.