Tests of motor laterality and behavioral reactivity, as well as salivary cortisol concentrations, were examined in this pilot study to identify dogs best suited to guide dog work. Over a 14-month period, lateralization tests were conducted and cortisol concentrations were determined on 3 separate occasions, and temperament testing was performed on 2. Potential guide dogs (N = 43) involved in this study were 5 golden retrievers (4 males, 1 female) and thirty-eight Labrador retrievers (8 black males, fifteen yellow males, 5 black females, and ten yellow females). Results from these tests were then compared with the ultimate success of the dogs in the Guide Dogs NSW/ACT training program. This comparison produced evidence that motor lateralization (particularly the rate at which both paws were used during the Kong Test and the lateralization index during the Tape Test), reactions to an unfamiliar dog, the latency for dogs to drop and rest during an uninterrupted period, and the dog's color and breed were predictive of ultimate success. This study also identified 14 months of age as a more accurate time to assess dogs for these traits than either 6 months of age or at the age at which they completed their training (ranging from 14 to 20 months of age).