Abstract. The effects of 12 hr nicotine administration and abstinence on stress-induced cardiovascular reactivity were assessed within Light/Intermittent cigarette smokers and Habitual cigarette smokers. One hundred thirty-two male smokers (66 Habitual, 66 Light/Intermittent) were assigned to a Nicotine (21 mg) or Placebo patch condition. Cardiovascular reactivity was assessed during Baseline, a 6-min mental arithmetic task (Paced Auditory Serial Arithmetic Task) and a 5-min mirror-tracing task (Star Mirror Tracing Task). Within the Nicotine condition, Light/Intermittent smokers showed greater cardiac output (CO) increases, smaller stroke volume decreases, and smaller total peripheral resistance (TPR) increases than Light/Intermittent smokers in the Placebo condition. No condition differences in cardiovascular reactivity were demonstrated for Habitual smokers. Light/Intermittent smokers also showed greater CO increases than Habitual smokers during the mirror-tracing task but during the Nicotine condition only. During mental arithmetic, Light/Intermittent smokers had greater CO increases and smaller TPR increases than Habitual smokers across nicotine conditions. Habitual smokers responded to stress with increases in peripheral responses whereas Light/Intermittent smokers responded myocardially. Light/Intermittent smokers may have increased density of β-adrenergic receptors whereas Habitual smokers may have decreased density due to chronic smoking.