Cultured spinal motoneurons are a valuable tool for studying the basic mechanisms of axon and dendrite growth and also for analyses of pathomechanisms underlying diseases like amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). As motoneurons in the developing spinal cord of mice constitute only a minor population of neurons, these cells need to be enriched in order to study them in the absence of contaminating neuronal and non-neuronal cells. Here, we describe a protocol for the isolation and in vitro cultivation of embryonic primary motoneurons from individual mouse embryos. Tissue dissection, cell isolation and a p75NTR-antibody-based panning technique, which highly enriches motoneurons within <8 h are described. This protocol is aimed to provide an alternative to the established FACS-based protocols describing p75NTR-based enrichments of neurons. This protocol will help in facilitating the research on molecular mechanisms underlying motoneuron development, survival and disease mechanisms.