Radiolabeled peptides derived from ubiquicidine (UBI) are of great interest for early and highly accurate scintigraphic detection and differentiation of infection and sterile inflammation. In the present work the recombinant antimicrobial peptide UBI18-35 - a fragment of the human natural cationic peptide ubiquicidine - was produced in Escherichia coil for the first time. The insoluble expression of the peptide in fusion with ketosteroid isomerase provided high yield, about 6 mg of UBI18-35 per liter. We developed an approach to produce the antimicrobial peptide UBI18-35, that encompasses inclusion body isolation and size exclusion chromatography. This method could be the basis for industrial biotechnological production of diagnostic system components that are in high demand.