Gelatinase B, as one of the matrix metalloproteinases, may be relevant to atherogenic plaque development and stability. Recently, a C-1562T substitution in the regulatory region of the gelatinase B gene was shown to up-regulate gelatinase B expression, which could be relevant to both the severity and stability of atherosclerotic plaques. We determined the genotype of 788 angiographically documented Caucasian patients with coronary artery disease (583 males and 205 females; age 56.7+/-0.4 years). The proportions of C/C (77.1%), C/T (21.4%) and T/T (1.5%) genotypes were in Hardy-Weinberg equilibrium, and did not differ between males and females (P>0.05). The frequencies of the rare T allele in patients with angiographically documented coronary artery disease (0.123), a past history of myocardial infarction (0.128) or unstable angina (0.128) were not significantly different from those in patients without such events (0.121, 0.118 and 0.128 respectively; P>0.05). In addition, the rare allele frequencies among patients with no (0.128), one (0.124), two (0.108) or three (0.121) significantly diseased vessels (> or =50% luminal obstruction) were not statistically different (P=0.932). However, the male rare T/T homozygotes had lower waist/hip ratios and levels of high-density lipoprotein cholesterol (HDL-C), and higher total cholesterol/HDL-C ratios, than C/C homozygotes (P<0.05). In conclusion, our study in a large series of angiographically defined patients suggests that the C-1562T polymorphism may not be useful as a predictor of the presence and severity of coronary atherosclerosis.