Urine wetting properties may influence the design and performance of catheters, urinalysis instruments, and lab-on-a-chip technologies. In this study the advancing contact angle theta(adv) of urine on several materials is characterized. Material type and surface tension have a significant effect on theta(adv), while pretreatment and aging do not. Mean urine theta(adv) are between approximate to 78 degrees and approximate to 89 degrees on hydrophilic surfaces, and up to over approximate to 105 degrees on hydrophobic surfaces. Expected urine contact angles will decrease from the DI water contact angles by on average 10 degrees, and up to 20 degrees, while urine surface tension will be lower than DI water by 12.12 mN/m and 18.53 mN/m. A unit change (mN/m) in surface tension results in a 0.75 degrees change in theta(adv). These results indicate that systems attempting to exploit urine wetting must account for highly variable conditions. (C) Koninklijke Brill NV, Leiden, 2009