Many disease-associated variants identified by genome-wide association (GWA) studies are expected to regulate gene expression. Allele-specific expression (ASE) quantifies transcription from both haplotypes using individuals heterozygous at tested SNPs. We performed deep human transcriptome-wide resequencing (RNA-seq) for ASE analysis and expression quantitative trait locus discovery. We resequenced double poly(A)-selected RNA from primary CD4+ T cells (n = 4 individuals, both activated and untreated conditions) and developed tools for paired-end RNA-seq alignment and ASE analysis. We generated an average of 20 million uniquely mapping 45 base reads per sample. We obtained sufficient read depth to test 1371 unique transcripts for ASE. Multiple biases inflate the false discovery rate which we estimate to be ∼50% for random SNPs. However, after controlling for these biases and considering the subset of SNPs that pass HapMap QC, 4.6% of heterozygous SNP-sample pairs show evidence of imbalance (P