Background: Pain management clinics are major sources of prescription opioids. Texas government passed several laws regulating pain clinics between 2009 and 2011 to reduce opioid-related toxicity. Understanding the impact of these laws can inform policy geared toward making the laws more effective in curbing the growing epidemic of opioid overdose, especially among the elderly population. Objectives: To examine the longitudinal association of laws regulating pain clinics on opioid-prescribing and opioid-related toxicity among Texas Medicare recipients. Methods: The 2007 to 2012 claims data for Texas Medicare Part D recipients were used to assess temporal trends in the percentage of patients filling any schedule II or schedule III opioid prescription, hospitalization for opioid toxicity, and their relationships to the 2009 to 2011 Texas laws regulating pain clinics. We excluded those with a cancer diagnosis. Join-point trend analysis with Bayesian Information Criterion selection methods were used to evaluate the change in monthly percentages of patients filling opioid prescriptions and hospitalization over time. Results: There was a short-lived decline in the monthly percentages of patients who filled a schedule II or schedule III opioid prescription after the 2009 laws regulating pain clinics. The decline lasted about 3 months. Subsequent new laws had no effect on the percentages of patients who filled any opioid prescription or were hospitalized for potential opioid toxicity. Hospitalizations for opioid toxicity were highest in the winter and lowest in the summer. Conclusions: Changes in the percentages of opioid-prescribing or opioid-related hospitalizations over time were not associated with laws regulating pain clinics.