Sleep problems have been reported as an adverse effect of statins. In a randomised trial, simvastatin at 20 mg produced significantly worse sleep quality than either placebo or pravastatin 40 mg. A possible relation to sleep apnoea was hypothesised. Here, the case of a 67-year-old man who experienced sleep apnoea on simvastatin 20 mg is presented. Objective nightly testing showed a prompt, marked, sustained and statistically significant improvement in the obstructive apnoea index when the patient switched to pravastatin 20 mg.