To investigate the physical characteristics and the bactericidal and sporicidal potential of a polymer-encapsulated ClO2 coating. An antimicrobial coating based on polymer-encapsulated ClO2 was developed. A low viscosity, water/oil/water double emulsion coating was formulated for easy on-site application. Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus were applied onto the coating to study the bactericidal capabilities of the coating. The bactericidal performance of the coating increased when the contact time with the tested bacteria increased. Over 99% of the E. coli, Ps. aeruginosa, B. subtilis were killed with a contact time of 30 min. Although endospores of B. subtilis are more resistant, about 75% of the spores were killed after 72 h on the coating. Moreover, a sustained release of gaseous ClO2 was achieved to maintain about 90% removal of B. subtilis with a 10-min contact time during a 28-day study period. The coating also exhibits antiadhesive properties against bacteria. A polymer-encapsulated ClO2 coating with sustained release of ClO2 and promising bactericidal and sporicidal features was tested for 28 days. This study provides a new direction for developing polymer-encapsulated ClO2 coatings that possess persistent bactericidal and sporicidal properties.