<p>Early-stage microbial colonization remains a major challenge for biomedical devices based on titanium alloys. In this study, a plasma-assisted surface functionalization strategy was developed to impart antibacterial and antifungal properties to anodized aluminum-free β-titanium alloys. Surface modification was performed by anodization followed by plasma polymerization of oxazoline under different discharge powers. Chlorhexidine, used as a clinically relevant antimicrobial model, was incorporated via immersion onto anodized and oxazoline-coated surfaces. Antimicrobial performance was evaluated against <i>Staphylococcus aureus</i> and <i>Candida albicans</i> biofilms. Oxazoline-modified surfaces exhibited a significant reduction in <i>C. albicans</i> colonization. At the same time, the combined oxazoline–chlorhexidine system resulted in a pronounced decrease in both bacterial and fungal viability compared with untreated controls. In vitro assays using pre-osteoblastic cells revealed reduced cell adhesion and viability on chlorhexidine-loaded surfaces, indicating a trade-off between antimicrobial efficacy and cytocompatibility. The results demonstrate that plasma-polymerized oxazoline acts as an effective functional interlayer, enabling antimicrobial loading and selective modulation of microbial adhesion on anodized β-Ti surfaces. This surface modification is particularly suitable for non-implantable biomedical applications, where contact with biological fluids may occur without requiring cell adhesion or tissue integration. Under these conditions, the observed antimicrobial efficacy becomes the primary functional advantage of the system.</p> Graphical abstract <p>Graphical elements generated by Generative AI and modified by the authors.</p> <p></p>