INTRODUCTION: Skin problems are commonly reported by amputees due to perspiration discomfort inside the prosthesis. Cotton is commonly used in prosthetic socks but its properties are not ideal. This study compared the banana-polyester sock dyed with guava extract (GuaBaNIKA) and cotton socks in terms of air permeability, absorbency and antibacterial activity. METHODS: This was a quantitative quasi-experimental study that compared GuaBaNIKA and cotton socks in terms of air permeability, absorbency and antibacterial activity using standard tests. Fibers from banana pseudostem were mixed with polyester, processed into yarn then fabric and dyed with guava leaf extract. Air permeability was analyzed using Mann-Whitney U Test and descriptive analysis was used for absorbency and antibacterial activity. RESULTS: The mean air permeability for GuaBaNIKA was significantly higher than that of cotton (295.5 vs 112.7 cm3/s/cm2). The air permeability scores were higher in GuaBaNIKA in all 10 specimens tested. GuaBaNIKA absorbed water faster than cotton (< 1 vs > 60 seconds). Both GuaBaNIKA and cotton knit socks did not produce a zone of inhibition. CONCLUSION GuaBaNIKA is more absorbent and permeable than cotton but did not exhibit antibacterial activity. GuaBaNIKA has the potential to be an alternative to cotton in prosthetic socks.