The mouse *H19* gene, identified as a fetal-specific mRNA under the control of the *raf* locus, lacks a detectable protein product despite multiple translation termination signals. To investigate its function, the human *H19* gene was cloned and sequenced, revealing no conserved open reading frames (ORFs) between the two homologs. Cellular fractionation showed that *H19* RNA is cytoplasmic but not associated with the translational machinery, instead forming a particle with a sedimentation coefficient of approximately 28S. Despite being transcribed by RNA polymerase II and undergoing splicing and polyadenylation, the *H19* RNA is not a classical mRNA. The authors suggest that the product of this unusual gene may be an RNA molecule, similar to other structural RNAs involved in RNA processing, protein transport, and synthesis. The conservation between mammalian and avian *H19* genes indicates a common function, possibly unrelated to protein encoding. Future research will focus on the nature of the cytoplasmic particle containing *H19* RNA and the phenotypic effects of overproducing wild-type and mutant RNAs in vivo.The mouse *H19* gene, identified as a fetal-specific mRNA under the control of the *raf* locus, lacks a detectable protein product despite multiple translation termination signals. To investigate its function, the human *H19* gene was cloned and sequenced, revealing no conserved open reading frames (ORFs) between the two homologs. Cellular fractionation showed that *H19* RNA is cytoplasmic but not associated with the translational machinery, instead forming a particle with a sedimentation coefficient of approximately 28S. Despite being transcribed by RNA polymerase II and undergoing splicing and polyadenylation, the *H19* RNA is not a classical mRNA. The authors suggest that the product of this unusual gene may be an RNA molecule, similar to other structural RNAs involved in RNA processing, protein transport, and synthesis. The conservation between mammalian and avian *H19* genes indicates a common function, possibly unrelated to protein encoding. Future research will focus on the nature of the cytoplasmic particle containing *H19* RNA and the phenotypic effects of overproducing wild-type and mutant RNAs in vivo.