Part I of this article (J Am Acad Dermatol 1989; 20:537-63) focused on normal sweat gland function. Part II provides a discussion of hyperhidrosis and hypohidrosis. Hyperhidrotic disorders affect the palms and soles and the axillae and are associated with previous spinal cord injuries, peripheral neuropathies, brain lesions, intrathoracic neoplasms, systemic illness, and gustatory sweating. Hypohidrotic disorders include anhidrotic ectodermal dysplasia, hereditary sensory neuropathy, Holmes-Adie syndrome, and generalized anhidrosis.