This study identifies seven loci associated with mean leukocyte telomere length (LTL), including five novel loci, through a genome-wide meta-analysis of 37,684 individuals and replication in 10,739 individuals. Five of the loci contain genes involved in telomere biology (TERC, TERT, NAF1, OBFC1, RTEL1). The lead SNPs at two loci (TERC and TERT) are associated with several cancers and other diseases, including idiopathic pulmonary fibrosis. A genetic risk score combining lead variants at all seven loci shows that alleles associated with shorter LTL are significantly associated with an increased risk of coronary artery disease (CAD) (21% (95% CI: 5–35%) per standard deviation in LTL, p=0.014). These findings support a causal role of telomere length variation in age-related diseases.This study identifies seven loci associated with mean leukocyte telomere length (LTL), including five novel loci, through a genome-wide meta-analysis of 37,684 individuals and replication in 10,739 individuals. Five of the loci contain genes involved in telomere biology (TERC, TERT, NAF1, OBFC1, RTEL1). The lead SNPs at two loci (TERC and TERT) are associated with several cancers and other diseases, including idiopathic pulmonary fibrosis. A genetic risk score combining lead variants at all seven loci shows that alleles associated with shorter LTL are significantly associated with an increased risk of coronary artery disease (CAD) (21% (95% CI: 5–35%) per standard deviation in LTL, p=0.014). These findings support a causal role of telomere length variation in age-related diseases.