Food deprivation stimulates foraging, hoarding and to a much lesser extent food intake, in Siberian hamsters. Leptin, the anorexigenic hormone secreted primarily from adipocytes, may act in the periphery, the brain or both to inhibit these ingestive behaviors. Therefore, we tested whether leptin given either intracerebroventricularly (icv) or intraperitoneally (ip), would block food deprivation-induced increases in food hoarding, foraging and intake in animals with differing foraging requirements. Hamsters were trained in a running wheel-based food delivery foraging system coupled with simulated burrow housing. We determined the effects of food deprivation and several peripheral doses of leptin on plasma leptin concentrations. Then hamsters were food deprived for 48 h and given ip leptin (0, 10, 40 or 80 µg), and additional hamsters were food deprived for 48 h and given icv leptin (0, 1.25, 2.5 or 5.0 µg). Foraging, food intake and hoarding were measured post-injection. Food deprivation stimulated food hoarding to a greater degree and duration than food intake. In animals with a foraging requirement, icv leptin almost completely blocked food deprivation-induced increased food hoarding and intake, but increased foraging, whereas peripheral leptin treatment was most effective in a sedentary control group, completely inhibiting food deprivation-induced increased food hoarding and intake at the two highest doses, and did not affect foraging at any dose. Thus, the ability of leptin to inhibit food deprivation-induced increases in ingestive behaviors differs based on foraging effort (energy expenditure) and the route of administration of leptin administration.