The purpose of this study was to evaluate the use of a body condition scoring system as a tool to manage body weight in our dog colony. We believe that body condition extremes have a pronounced potential impact on pharmaceutical assessment studies. We selected animals from our colony for participation in a dietary management program based on body condition scoring and body weight. Dietary amount was adjusted according to the current and desired conditions of the animal. Animals were re-evaluated monthly, and diet was adjusted based on the progress the animal was making toward its goal. Retrospective analysis of the data showed that approximately 3 months of enrollment in the dietary management program was required to optimize body condition in our dogs. Nearly twice as many female than male animals were enrolled in the program for weight loss, and they were enrolled at a significantly younger age (784.3 days versus 1063.9 days, respectively, P = 0.02). Nearly six times as many female animals were enrolled for weight loss as weight gain. Conversely, twice as many males than females were enrolled for weight gain, but differences in age for these animals were not significant. There was a significant negative correlation (-0.68, P < 0.01) between age and rate of loss of body condition for female dogs. Body condition scoring was a less sensitive indicator of progress on the program than was body weight, with a 6.5% to 7.2% change in body weight seen for each incremental change in score. It took between 2 and 4 months for the body condition score to change by one increment. Correlations between change in body condition and body weight were poor, except in the group of male animals enrolled for weight loss (0.84, P < 0.01). We conclude that body condition scoring is useful for dietary management of a dog colony within the time frame we have described, with the caveat that correlations between weight change and body condition score change is somewhat variable. Older female dogs offered particular challenges for management of obesity.