Objective Morphological heterogeneity and the expression of neuropeptides in the cultured primary neurons of the dorsal root ganglia from the embryonic mouse were investigated.Methods Morphology and neurochemistry of cultured dorsal root ganglia (DRG)neurons were analyzed by phase-contrast microscopy and immnuofluorensence. Results Morphological characteristics of DRG neurons with a 3-week culture period appeared similar to those observed in adult DRG neurons. The ratio of median to small sized neurons (20-30μm) was increased from (8.9±0.61)% after 1-week culture to (29.58±1.23)% after 3-weeks culture. The selective neuropeptides,CGRP, substance-P, galanin and nociceptin, were expressed in neuron soma from the first week of the culture. After 3 weeks of culture, an obvious immunoflurensent express of the peptides in neuronal processes was observed. In addition, most neurons containing calicitonin gene related peptide(CGRP) and substance-P belonged to small-size DRG neurons in 3-weck-old DRG culture, which was similar to the features of adult spinal DRG neurons. The morphological features of galanin- and nociceptin-positive neurons didn’t show any difference from 1-week to 3-week culture.Conclusion The embryonic mouse DRG neuron culture might be set up as an in vitro model for the study on some important sensory neuropeptides, like CGRP, substance-P, and their roles in modulating intracellular signaling pathways for sensati