Estimating effective doses of novel HIV vaccines is challenging. Dose-response analyses of DNA and fowlpox virus HIV vaccines showed that 1 mg of DNA vaccine and 5 × 107pfu of fowlpox virus booster was immunogenic in macaques. However, this dose was poorly immunogenic in humans. When adjusted for body surface area, the human dose studied was equivalent to a poorly immunogenic lower dose in monkeys. These data provide a rationale for guiding dosing in future trials of HIV vaccine technologies.