Updated project metadata. Human umbilical vein endothelial cells (HUVECs) are a widely-used model system to study many pathological and physiological processes associated with the cardiovascular system. An understanding of genes and proteins that are expressed in any cell type is a fundamental need which facilitates study of molecular changes in disease states and response to various stimuli. In this study, we employed next generation sequencing and mass spectrometry to profile the transcriptome and proteome of primary HUVECs. Analysis of 145 million paired-end reads from next generation sequencing confirmed expression of 12,186 protein-coding genes (FPKM>0.1), 439 novel long non-coding RNAs and revealed 6,089 novel isoforms that were not annotated in GENCODE. A comparison of the transcripts against human gene expression data for 53 tissues catalogued by the Genotype-Tissue Expression (GTEx) project revealed a number of HUVEC-specific genes. Proteomics analysis identified 6,477 proteins including confirmation of N-termini for 1,091 proteins and isoforms for 149 proteins for which transcriptomic evidence was also observed. Alternate translational start sites for seven proteins and alternate splicing in seven proteins were also identified. A database search to specifically identify other post-translational modifications provided evidence for a number of modification sites on 117 proteins which include ubiquitylation, lysine acetylation, mono, di- and tri-methylation. Based on the data from this study and a survey of other databases, we provide evidence for 11 ???missing proteins,??? which are proteins for which protein level evidence is lacking or insufficient. Proteogenomic analysis identified novel N-termini and exon-exon junctions at both RNA and protein levels by searching against a translated database created from alternate transcript assembly. Peptides supporting the novel events of expressed proteins are further validated by synthesis and spectral comparison. Alternative allelic expression of genes arising from transcription of two alleles of a gene in chromosome pairs is observed. By creating a custom database of proteins incorporated with sample specific single amino acid variations (SAAV) we identified alternative alleles for 207 expressed proteins with 245 peptides with SAAV. Overall, we believe that the integrated approach employed in this study is widely applicable to study any primary cell type for deeper molecular characterization.