Background: The developing nervous system consists of a variety of cell types. Animal models that allow the visualization of specific classes of neurons are crucial for the study of neuronal networks. Results: We performed an enhancer trap screening in zebrafish and generated a collection of transgenic lines that expressed GFP in a spatially and temporally restricted manner. Among the fish generated, we identified an insertion of the enhancer trap construct in the vicinity of the mnr2b/hlxb9lb gene encoding the mnx class of homeodomain transcription factor. The insertion gave rise to GFP expression predominantly in spinal motor neurons and abducens motor neurons. During embryogenesis, GFP expression was also detected in endodermal and mesodermal tissues, where mnr2b is known to be expressed. Conclusion: These results show that the enhancer trap construct recapitulated the expression pattern of the mnr2b gene and this transgenic line should be useful for the visualization of the spinal and abducens motor neurons in the developing nervous system. Developmental Dynamics 241:327–332, 2012. © 2011 Wiley Periodicals, Inc.