To assess the relationship between various physical and clinicopathologic parameters and the capillary refill time (CRT) using a standard method; to evaluate the influence of emergency room (ER) versus ICU hospital location on CRT; and to identify latent subgroups among the CRT distribution. Prospective, observational study. University teaching hospital. Client-owned dogs in the ER (n=40) and ICU (n=71). The CRT was defined as the duration required for the oral mucosa of the upper lip to return to its original color after blanching for 4 seconds. The CRT was recorded in seconds to the 10ths place by a single observer using an automated recording device. Median CRT for all dogs was 1.1 seconds (ER, 1.2 s; ICU, 1.1 s; P=1.000). The CRT was significantly associated with rectal temperature (P=0.004), systolic blood pressure (P=0.028), body weight (P=0.031), mucous membrane color (P=0.007), skin turgor (P=0.039), and acute patient physiologic and laboratory evaluation mentation score (P=0.019) for all dogs. The CRT was related to a greater number of variables in the ER than in the ICU patient population. In general, the total population of dogs had CRTs belonging to 1 of 2 groups: either≤1.2 or≥1.7 seconds. A statistically significant association was found between body weight CRT≥1.3 seconds (P=0.02). A CRT following blanching for 4 seconds may provide insight into the hydration status and hemodynamic stability of canine patients. Further research into its clinical application is warranted.