Diagnosis of lameness due to infectious claw lesions in beef cattle can be extremely challenging under commercial feedlot conditions resulting in inappropriate medical treatment and unnecessary drug and labor costs. The objective of this study was to determine if infrared thermography could be used to make a differential diagnosis between foot rot (FR) and digital dermatitis (DD) based on claw area temperatures. Over a 16-mo period, 470 lame cattle from the same commercial feedlot in Southern Alberta were examined while restrained in a squeeze chute. Thermographic images were taken using a Flir i40 infrared camera, and processed with ThermCam QuickView 1.3 (Flir Systems Inc., Burlington, ON, Canada) from the anterior and posterior views of each affected hoof, and the laterally adjacent unaffected hoof within the same animal, to obtain temperature differentials. Limb position (fore or hind) of the imaged hoof was also recorded. Temperatures from the underside view of the affected limb were also measured. Ambient temperature and relative humidity within the examination barn were recorded using a Hobo U23 Pro v2 logger (Onset Computer Corporation, Bourne, MA). After images were obtained, the affected hoof and lesion were cleaned with a brush and a physical exam was conducted to determine the actual cause of lameness. Data were analyzed using a mixed effect model with diagnosis, affected limb and their interaction as a main effects, and ambient temperature and relative humidity as covariates. No differences were observed in temperatures of unaffected and affected hooves for either FR or DD cases (−1.3 ± 0.22°C and −0.7 ± 0.37°C, respectively (P = 0.15) for the anterior view, and −0.9 ± 0.16°C and −1.2 ± 0.24°C, respectively (P = 0.41) for the posterior view). In addition, temperatures from the underside view were not different (P = 0.67) between FR (35.9 ± 0.12°C) and DD (35.8 ± 0.18°C). Under the conditions of this study, infrared thermography was not a useful tool for differentiating between beef feedlot cattle diagnosed with foot rot and digital dermatitis.