The existence of "hardcore" smokers, those most likely to have substantial difficulty quitting, may have far reaching impact on how to best allocate cessation resources. It has been suggested that hardcore smokers make up only a small fraction of current smokers and therefore do not represent a significant public health problem. However, little is known about the prevalence and nature of this subgroup of smokers in the United States. Based on a national sample, the 1998-1999 Tobacco Use Supplement to the Current Population Survey, we categorized, based on smoking pattern, groups of current smokers who were over age 25 years (N=33,568). We compared hardcore smokers with other groups of current smokers on demographic, environmental, and smoking variables to assess whether hardcore smokers represent a unique group. Hardcore smokers were defined as established daily smokers, consuming 15 or more cigarettes per day with no reported history of quit attempts. Hardcore smokers represent 13.7% of all current smokers and 17.6% of all established smokers. They are more likely to be male, unmarried, not in the work force, and have lower education. They also are more likely to have started smoking at a younger age, smoke more, and are less likely to report contact with smoking restrictions. This analysis suggests that hardcore smokers are distinct from other groups of smokers. These results also indicate that hardcore smokers account for a substantial proportion of smokers and as such may represent a significant public health challenge that needs to be addressed.