Objective: To ascertain whether carpal tunnel syndrome (CTS) in patients affected with toxic oil syndrome (TOS) is associated with conditions and diseases considered risk factors for CTS in the general population and/or with certain clinical manifestations of TOS. Methods: We conducted a case–control study to compare 89 TOS patients residing in Madrid diagnosed with CTS from 1981 through July 2001 (cases) against 638 TOS patients not affected with CTS (controls). Risk factors for CTS and clinical manifestations of TOS were analyzed. Results: Multivariate logistic regression analysis yielded the following odds ratios (95% confidence interval): 3.32 (1.47–7.50) for TOS-related neuropathy; 2.85 (1.14–7.13) for TOS-related thromboembolic events; 2.63 (1.36–5.06) for female gender; 0.43 (0.24–0.80) for TOS-related scleroderma; 0.26 (0.12–0.59) for smoking; and, in women, 2.53 (1.06–5.70) for fibrositis and 1.84 (1.04–3.20) for miscarriages. Conclusion: Our study findings support the hypothesis that CTS in TOS patients is more linked to certain clinical manifestations of TOS, mainly neuropathy, than to conditions and diseases considered risk factors for CTS in the general population.