Associations of race, smoking history and fibrinogen levels with cancer mortality were investigated prospectively using the ARIC study. Our cohort consisted of 14,320 participants aged 45-64 at baseline. In an adjusted Cox regression, black current heavy smokers (> or = 15 cigarettes per day) demonstrated higher risk of respiratory/intrathoracic organ cancer mortality than nonblack current heavy smokers. Black former heavy smokers were also found to be at an increased risk of respiratory/intrathoracic organ cancer mortality when compared to nonblack former heavy smokers. Elevated fibrinogen levels were associated with an increased risk of respiratory/intrathoracic organ cancer mortality. Compared to fibrinogen < 259 mg/dl, fibrinogen 294-335 mg/dl had an adjusted hazard ratio of 3.68 (95% CI: 1.80-7.55), and fibrinogen > or = 336 mg/dl had an adjusted hazard ratio of 3.78 (95% CI: 1.84-7.75). Fibrinogen was also a predictor of other types of cancer mortality among black participants, but not among nonblack participants. For 10 race/smoking history categories, fibrinogen levels ranged from a mean of 287 mg/dl for nonblack former light smokers to a mean of 338 mg/dl for black current heavy smokers. Smokers had higher fibrinogen levels than nonsmokers, and black smokers had higher fibrinogen levels than nonblack smokers. Smoking carries high risks of cancer mortality for African Americans. A factor that needs to be considered in the overall assessment of risk is fibrinogen level, which has been linked to angiogenesis and metastases of tumors.