We examined the association between prosthetic nonbreast implants and selected malignant neoplasms, connective tissue disorders, and neurologic diseases. We conducted a case-control study from an insurance claims database. We selected controls who had diseases for which no association with implants have been claimed or reported. Data were analyzed using both tabular and polytomous regression analysis methods, including methods to account for the large number of comparisons. All analyses exhibited positive associations between implants (both silicone and metal) and neurologic conditions, especially idiopathic progressive neuropathy and Meniere syndrome, as well as the expected associations with arthritic conditions. There also was an unexpected negative association between metal implants and brain tumors. In conclusion, further studies of prosthetic implants and neurologic diseases appear warranted. These studies should obtain medical histories to control for possible confounding effects of drug treatments associated with implant surgery.