The fields of dendrite arborization (projections) were examined in phrenic nuclei of adult cats. Six types (five radial and one longitudinal) of phrenic motoneuron dendrites have been determined. The radial dendrites can project to lamina VIII or VII, to lateral and ventrolateral locomotor nuclei and to all funiculi of the white matter surrounding the ventral horn. The ventrolateral, dorsomedial and ventromedial dendrites form separate bundles. The longitudinal dendrites extend rostrocaudally within the phrenic nucleus, forming the most potent bundle.