Calpains are a superfamily of Ca2+-dependent cysteine proteases, implicated in various cellular processes and thus probably necessary in all the stages of cell life. The first extended report of quantification of total RNAs within the developmental stages of Xenopus laevis was described in this study. Decreases of total RNAs were positively associated with waves of apoptotic cell death (onset of gastrulation, and morphogenesis). Using qPCR, the temporal expression pattern of CAPN1 and CPAN8b (XCL-2) were characterized during the Xenopus laevis embryogenesis. Transcripts of the CAPN1 and CAPN8 genes were detectable from gastrula stage and their levels oscillated throughout development. The expression of the CAPN1 (mu/I) gene was observed in earliest stage, indicating a maternal origin, while expression of the CAPN8b gene was detectable after midblastula transition. The levels of the two transcripts then started to rise again obviously as a result of zygotic expression (stage 11). The CAPN1 gene expression was particularly expressed at tailbud stage, while the CAPN8 transcripts were found at gastrula, neurula and tailbud stages. This is the first report of quantification of mRNAs CAPN8b and CAPN1 (mu/I) within the developmental stages of Xenopus laevis by qPCR.