Seventeen children, 6 girls and 11 boys, aged 5-17 years with pediatric median mononeuropathies (PMM) were identified among 1809 who had EMGs primarily in the electromyographic laboratory at The Children's Hospital, Boston, between 1979 and 1993. Electromyography documented the PMM to be at the wrist in 7 children, including 3 children with idiopathic carpal tunnel syndrome (CTS)--1 whose symptoms were accentuated by skiing--2 with a systemic illness (mucolipidosis III and scleroderma), and in 1 child each the distal PMM was secondary to a cast or laceration. A proximal PMM was identified in 10 children, including 8 with trauma, 1 with an osteoid osteoma, and 1 with juvenile cutaneous mucinosis. Five children (3 with CTS and 1 each with mucolipidosis III and juvenile cutaneous mucinosis) had bilateral disease. The localization (59% proximal) and cause of these PMMs differed greatly from our experience with adult median neuropathies.