We describe a study testing fibrillar β-amyloid 1–42 (Aβ 42 ) vaccination in dogs. Three young beagles (4.6 years) were immunized twice with Aβ 42 and a Th1 adjuvant (TiterMax Gold). Animals generated primarily IgG 2 and IgM antibody responses, which were specific for the Aβ 11–30 region of Aβ 1–42 . Next, 3 aged beagles (8.9–13.8 years) were immunized 4 times with Aβ 42 and a Th2 adjuvant (Alum). We observed an acute increase in IgG 2, a slower increase in IgG 1 and Aβ antibodies of broader specificity (Aβ 1–15> Aβ 11–30> Aβ 6–20 ). A nonsignificant increase in CSF Aβ 1–40 and decrease in Aβ 1–40/1–42 in cortex was detected. Canines may be a useful system for testing an Aβ vaccine.