PURPOSE: To assess the efficacy, dose stability, safety, and abuse potential of long-term, nightly benzodiazepine treatment of chronic disorders of disrupted nocturnal sleep. PATIENTS AND METHODS: During a 12-year period, one author evaluated and treated 170 adult referrals for ≥6 months with nightly benzodiazepine therapy for longstanding, sleep-disruptive disorders: injurious sleepwalking and sleep terrors (69); rapid eye movement sleep behavior disorder (52); chronic, severe insomnia (25); and restless legs syndrome/periodic limb movement disorder (24). RESULTS: Complete/substantial control of the sleep disorders was achieved by 146 patients (86%); 8% had adverse effects requiring medication changes; 2% had relapses of alcohol or chemical abuse requiring hospitalization; another 2% at times misused their medications. A total of 136 patients received clonazepam nightly for a mean 3.5 (± 2.4) years, with no significant difference in initial versus final mean dose: 0.77 mg (± 0.46) versus 1.10 mg (± 0.96). Similar results were obtained with chronic alprazolam treatment and with other benzodiazepine treatments. CONCLUSION: Long-term, nightly benzodiazepine treatment of injurious parasomnias and other disorders of disrupted nocturnal sleep resulted in sustained efficacy in most cases, with low risk of dosage tolerance, adverse effects, or abuse. Data from this study on the treatment of chronic, severe insomnia (a small subset of all insomnia) are net generalizable to the typical insomnia patient.