The effects of 24h of food deprivation on subjective, physiological and cognitive responses to marijuana were studied in 8 male marijuana smokers. A within-subjects design was used in which subjects smoked active (1.3% THC) and placebo (0.0% THC) marijuana in both a fed and a fasting state. Each of the four experimental conditions - Fed/Active, Fed/Placebo, Fast/Active, Fast/Placebo - was enacted twice according to a randomized block design. A controlled smoking regimen was employed which held inhaled volume of marijuana smoke constant across feeding conditions. Smoke inhalation was monitored by measuring expired-air carbon monoxide (CO) levels before and after smoking. Heart rate and subjective effects of marijuana were assessed before, during and after smoking. A measure of memory performance, free recall, was also assessed after smoking. CO absorption from both placebo and active marijuana did not differ across feeding conditions, indicating that smoke dose was similar across feeding conditions. Typical effects of marijuana, such as elevated heart rate, impaired memory and increased "high" ratings were obtained after smoking active marijuana, but fasting had no effect on the drug response. Lack of a food deprivation effect on marijuana subjective effects and memory performance was noted not only in all subjects, but also in a subset of subjects (n=6) whose physiological states provided verification of their fasting state in Fast sessions.