The effects of short-term deprivation of caffeinated beverages on mood, withdrawal symptoms, and psychomotor performance were studied in habitual coffee drinkers. Twenty-four male and female coffee drinkers were tested at midday (1130-1330 h) under two conditions. On one day they consumed caffeinated beverages ad lib prior to testing, and on the other they remained caffeine abstinent. The order of treatments was counterbalanced. Mood and withdrawal symptom reports were collected by questionnaires. Psychomotor performance was tested with a computerized test battery. Caffeinated-beverage deprivation was associated with decreased vigor and increased fatigue and with symptoms including headache. No changes in psychomotor performance were observed. Even short periods of caffeinated-beverage deprivation, equivalent in length to missing regular morning coffee, can produce noticeable unpleasant caffeine-withdrawal symptoms by the middle of the day. These symptoms may be a common side effect of habitual caffeinated beverage consumption.