Pairs of forward and reverse primers and TaqMan probes specific to each of 46 human ATP-binding cassette (ABC) transporters and 108 human solute carrier (SLC) transporters were prepared. The mRNA expression level of each target transporter was analyzed in total RNA from single and pooled specimens of various human tissues (adrenal gland, bone marrow, brain, colon, heart, kidney, liver, lung, pancreas, peripheral leukocytes, placenta, prostate, salivary gland, skeletal muscle, small intestine, spinal cord, spleen, stomach, testis, thymus, thyroid gland, trachea, and uterus) by real-time reverse transcription PCR using an ABI PRISM 7700 sequence detector system. In contrast to previous methods for analyzing the mRNA expression of single ABC and SLC genes such as Northern blotting, our method allowed us to perform sensitive, semiautomatic, rapid, and complete analysis of ABC and SLC transporters in total RNA samples. Our newly determined expression profiles were then used to study the gene expression in 23 different human tissues, and tissues with high transcriptional activity for human ABC and SLC transporters were identified. These results are expected to be valuable for establishing drug transport-mediated screening systems for new chemical entities in new drug development and for research concerning the clinical diagnosis of disease.