Increased plasma fibrinogen level is an important prognostic factor of recurrent unstable angina and myocardial infarction in patients with acute coronary syndrome (ACS). The aim of our study was to assess the plasma fibrinogen level at baseline condition in patients admitted to hospital due to coronary artery disease (CAD). Plasma fibrinogen was measured in 51 consecutive patients presenting with ACS within the last 24 hours and in 50 patients with angiographically proven CAD that was stable for the past 30 days. For statistical analysis Mann-Whitney U test, Student t-test, chi-square test and Pearson correlation was used, p < 0.05 being considered statistically significant. There was significant correlation between fibrinogen level and diagnosis of ACS or CAD (r = 0.29, p = 0.002). In our population plasma fibrinogen levels (g/L +/- SD) were significantly different in patients with ACS when compared to CAD subjects (3.87 +/- 1.2 vs. 3.26 +/- 0.65, p = 0.002). There was difference between ACS and CAD subjects in male:female ratio (40/11 vs. 47/4, p < 0.001) and age (63.4 +/- 10.1 vs. 58.4 +/- 10.0, p = 0.014). Our results confirm the role of fibrinogen in pathogenesis of CAD. In our opinion plasma fibrinogen level may be an important diagnostic tool in assessment of patients with chest pain.