Some polymorphisms in genes codifying for fibrinogen have been correlated with plasma levels of this protein, and several studies reported their associations with acute cardiovascular events. In the present study, 118 subjects with unstable and stable coronary diseases were enrolled to determinate the associations among fibrinogen gene polymorphisms, plasma fibrinogen levels, and major cardiovascular adverse events in a sample of southwestern Mexico. The groups, including 81 control subjects, were matched for age, sex, body mass index, and sedentarism. Plasma fibrinogen levels and the polymorphisms 455G/A, -148C/T, +1689T/G, and Bcl I of the gene of fibrinogen were compared in all groups. Plasma fibrinogen levels (>465 mg/dl) were significant in patients with coronary disease. Fibrinogen plasma values > 450 mg/dl were associated with cardiovascular mortality during the follow-up analysis of the unstable coronary disease group (p = 0.04). The allelic loads of -455A and -148T were associated with plasma fibrinogen levels > 450 mg/dl (p < 0.003 and p = 0.03, respectively) and with coronary disease (p = 0.016 and p < 0.006, respectively). The follow-up of posterior events after an acute coronary event showed that the genetic load of the -148T allele was associated with major adverse cardiovascular events (RR = 1.8, 95%CI = 1.01-3.35, p = 0.04). Fibrinogen plasmatic levels > 450 mg/dl and the fibrinogen polymorphisms -455G/A and 148C/T had association with MACE and coronary disease. This study suggests that these gene polymorphisms are associated with cardiovascular risk.