RNA binding proteins play key roles in the post-transcriptional regulation of gene expression. Here we present the molecular cloning and spatio-temporal expression of Xseb-4, which codes for a putative RNA binding protein containing a single RNA recognition motif (RRM). XSEB-4 shares 60-65% identity with the mammalian SEB-4 proteins. Xseb-4 is strongly expressed maternally. Zygotic transcription is initiated in the early gastrula embryo in paraxial mesoderm that is fated to give rise to somites. During the course of gastrulation and neurulation Xseb-4 expression in somitic paraxial mesoderm is centered within the XmyoD expression domain. As development proceeds Xseb-4 expression is in addition initiated in the cardiac primordium and the lens vesicle. In the heart expression is confined to the myocardium. Thus, the RRM-containing putative RNA binding protein XSEB-4 is differentially expressed during embryonic development in Xenopus.