The aim of the present investigation was to extend previous work on anxiety sensitivity (AS) and early smoking relapse among a sample of 130 (74 females) young adult (M (age) = 22.5 years, SD = 2.1) daily low-level smokers (9.3 cigarettes/day, SD = 11.5) from Mexico City, Mexico. Results indicated that of the global-level and lower-order factors (i.e., physical, mental incapacitation, and social concerns) on the Anxiety Sensitivity Index, only the physical concerns factor was significantly related to early lifetime smoking relapse. This effect was observed above and beyond the effects of negative affectivity, cigarettes smoked per day, and alcohol consumption, as well as beyond the other AS mental and social concerns factors. Findings provide novel evidence that AS is an important explanatory construct in early smoking relapse.