Dynamic changes in DNA methylation at the gene-specific and genome-wide level occur during mammalian germ-cell development. However, the details of how the methylation profiles change remain largely unknown. Bisulfite sequencing analysis is a powerful technique to determine the methylation status of DNA at individual cytosine-guanine dinucleotide (CpG) sites and requires only a small amount of DNA for analysis. Here, we introduce two methods for bisulfite-based DNA methylation analyses using small samples such as germ cells: bisulfite Sanger sequencing at a specific locus and high-throughput bisulfite sequencing at the whole genome level.