Patients with motor neuron diseases may present to primary care clinic or may be initially encountered in the inpatient setting. Timely diagnosis of these conditions is a key factor in early intervention and therapy, and accuracy of diagnosis is of extreme importance, in particular for amyotrophic lateral sclerosis with its poor prognosis. The aim of this review article is to provide a clinical and diagnostic framework for the diagnosis and evaluation of motor neuron disease for primary care physicians.