Circulating proteins are prognostic for human outcomes including cancer, heart failure, brain trauma and brain amyloid plaque burden. A deep serum proteome survey recently revealed close associations of serum protein networks and common diseases. The present study reveals unprecedented number of individual serum proteins that overlap genetic signatures of diseases emanating from different tissues of the body. Here, 55,932 low-frequency and common exome-array variants were compared with 4782 protein measurements in the serum of 5457 individuals of the deeply annotated AGES Reykjavik cohort. At a Bonferroni adjusted P-value threshold < 2.1610 -10 , 5553 variants affecting levels of 1931 serum proteins were detected. These associated variants overlapped genetic loci for hundreds of complex disease traits, emphasizing the emerging role for serum proteins as biomarkers of and potential causative agents of multiple diseases.Large-scale genome-wide association studies (GWASs) have expanded our knowledge of the genetic basis of complex disease. As of 2018, approximately 5687 GWASs have been published revealing 71,673 DNA variants to phenotype associations 1 . More recently, exomewide genotyping arrays have linked rare and common variants to many complex traits. For example, 444 independent risk variants were identified for lipoprotein fractions across 250 genes 2 . Despite the overall success of GWAS, the common lead SNPs rarely point directly to a clear causative polymorphism, making determination of the underlying disease mechanism difficult 3-6 . Regulatory variants affecting mRNA and/or protein levels and structural variants like missense mutations can point directly to the causal candidate. Alteration of the amino acid sequence may affect protein activity and/or influence transcription, translation, stability, processing and secretion of the protein in question 7-9 . Thus, by integrating intermediate traits