Two cotton fabrics were treated with increasing amounts of a textile-finishing agent (1,3-dimethyl-4,5dihydroxy-2-imidazolidinone) to impart durable press properties. The Universal Attenuated Total Reflectance Fourier Transform Infrared (UATR-FTIR) with a ZnSe-Diamond composite crystal was used to determine the amount of the crosslinking agent effectively linked to the cellulose after the required laundering cycles. Textile performance testing conducted on treated and untreated fabrics demonstrated the effectiveness of the treatment applied. The results obtained showed very good correlation between AATCC grading, automatic image analysis of fabric smoothness, textile performance testing, and the amount of finish as evaluated by the UATR-FTIR. The ZnSe-Diamond composite FTIR accessory was proven to be a fast and precise nondestructive technique to evaluate the amount of the crosslinking agent linked to the cellulose macromolecules. (C) 2005 Wiley Periodicals, Inc.