Library quantitation is a critical step to obtain high data output in Illumina HiSeq sequencers. Here, we introduce a library quantitation method that uses the Illumina MiSeq sequencer designated as quantitative MiSeq (qMiSeq). In this procedure, 96 dual-index libraries, including control samples, are denatured, pooled in equal volume, and sequenced by MiSeq. We found that relative concentration of each library can be determined based on the observed index ratio and can be used to determine HiSeq run condition for each library. Thus, qMiSeq provides an efficient way to quantitate a large number of libraries at a time. (C) 2014 Elsevier Inc. All rights reserved.