Two 2-month-old Griffon Briquet Vendéen pups from the same litter were evaluated for progressive weakness and hind limb paresis. The paraparesis progressed rapidly to extensor paralysis with subsequent involvement of the forelimbs with flexor paralysis. The appendicular muscles of all four limbs became progressively atrophied. Lesions included severe loss of neurons in the ventral horns of the spinal cord, Wallerian degeneration of ventral spinal roots, and peripheral nerve and neurogenic appendicular muscular atrophy. The clinical and morphological findings were consistent with a progressive lower motor neuron disease.