DNA methylation is a major epigenetic mark associated with multiple aspects of retrotransposons within the mammalian genome. In order to study DNA methylation of a large number of retrotransposons on an individual-locus basis, we have developed a new protocol termed High-Throughput Targeted Repeat Element Bisulfite Sequencing (HT-TREBS) (Ekram and Kim, 2014 [1]). We have used this technique to characterize the locus-specific patterns of DNA methylation of 4799 members of the mouse IAP LTR (Intracisternal A Particle Long Terminal Repeat) retrotransposon family in embryonic stem, somatic and Neuro2A cells (Bakshi and Kim, 2014 [2]). Here we describe in detail the sample preparation and bioinformatics analyses used for these studies. The somatic cell data may be accessed under GEO accession number GSE49222. The ES and Neuro2A data are deposited under GEO accession number GSE60007.