Background: Flexibility in the time of administration of statin therapy is likely to improve patient compliance. This study compared the efficacy and tolerability of morning and evening administration of the extended-release formulation of fluvastatin (fluvastatin XL). Methods: In this prospective, double-blind, multicenter, multiple dose study, 236 patients with type IIa/b hypercho lesterolemia were randomized to receive fluvastatin XL, 80 mg, in the morning or evening for 8 weeks. Results: At 8 weeks, low-density lipoprotein cholesterol levels were reduced by 34.5 and 35.0% in the morning and evening treatment groups, respectively (p = 0.0118 for non-inferiority of morning administration). There were no statistically significant differences between the morning and evening treatment groups in the changes in total cholesterol (p = 0.56), high-density lipoprotein cholesterol (p = 0.21), triglycerides (p = 0.13), apolipoprotein B (p = 0.66) and apolipoprotein AI (p = 0.88) at 8 weeks. The frequency of adverse events was slightly lower in the morning treatment group compared with the evening treatment group (27.4 vs. 35.5%). Conclusions: The efficacy and safety profiles of fluvastatin XL are equivalent for morning and evening administration.