Pipe and cigar smokers traditionally have been subdivided into primary (never regular cigarette) and secondary (ex-cigarette) smokers. This distinction is considered important because it is believed that former cigarette smokers who switch to pipes or cigars inhale their pipe or cigar smoke, whereas primary pipe and cigar smokers do not. In this study, it was found that self-reported inhalation more accurately predicted expired-air carbon monoxide levels than cigarette smoking history and, combined with self-reported per day consumption, could account for most instances of carbon monoxide levels above the non-smoker cut-off level of 8 parts per million. Thus, it is concluded that a primary/secondary distinction is less useful than a noninhaling/inhaling distinction in attempting to assess health risks associated with pipe and cigar smoking, and health-care providers and researchers should focus their attention on the more direct questions of inhalation and daily intake.