Objective: To evaluate the safety and effectiveness of chenodeoxycholic acid (CDCA) treatment in patients with cerebrotendinous xanthomatosis (CTX). Methods: Two retrospective cohort studies were conducted in CTX patients who underwent CDCA treatment: one in the Netherlands (NL; CDCA-STUK-15-001) and one in Italy (IT; CDCA-STRCH-CR-14-001). Eligible patients were aged 2–75 years, had been diagnosed with CTX, and were treated with CDCA orally for ≥1 year. The impact of CDCA treatment on biochemical markers (including serum cholestanol levels) and disease signs and symptoms were assessed, in addition to the safety and tolerability of CDCA treatment. Results: A total of 35 patients were screened in the NL study and were diagnosed with CTX at 25.6 (± 13.7 SD) years on average. These patients were treated with CDCA and followed up for a median of 9.00 (range: 0.4–26.3) years. In addition, 28 patients were enrolled in the IT study and were diagnosed at 35.0 (± 11.4 SD) years on average (median duration of CDCA treatment: 5.75 [range: 0.0–25.0] years). Signs and symptoms of disease resolved, improved, or remained stable in many patients, with concomitant improvements in biochemical marker levels (serum cholestanol, p < 0.001; 7α-hydroxy-4-cholesten-3-one, p < 0.001 [IT study]). Conclusions: The outcomes of these retrospective cohort studies indicate that CDCA is effective in the long-term treatment of CTX, with an acceptable safety profile. © 2019, The Author(s).