Introduction In the present study, we aimed to evaluate compliance to lipid lowering guidelines regarding statin prescription on discharge and statin adherence rates during a follow-up period of one year in patients hospitalised with a diagnosis of acute coronary syndrome (ACS). Methods In-hospital records of 3506 ACS patients, of which 771 had experienced an ST-elevation myocardial infarction (STEMI) and 2735 had experienced a non-STEMI, were collected. We calculated medication possession ratios (MPRs) for each subject. We designated patients with >= 9 statin refills/year (MPR >= 0.75) as the statin-adherent group and patients with <9 statin refills/year (MPR < 0.75) as the statin-non-adherent group. Results During a 12-month follow-up period, 234 patients in the STEMI group (30.3%) and 391 patients in the non-STEMI group (14.3%) had 12 refills of statin. Thus, only 17.8% of the total study population had complete adherence to statin therapy with an MPR of 1. When patients with >= 9 statin prescriptions were categorised as the statin-adherent group, only 1575 patients (44.9%) were found to be adherent to statin treatment. In multivariate analysis, patients with a non-STEMI diagnosis and high intensity statin treatment had higher rates of non-adherence (OR:1.685, 95%CI:1.412-2.012,p < .01 and OR:1.344, 95% CI: 1.147-1.574,p < .01, respectively). Patients with prior statin treatment had lower rates of non-adherence(OR:0.437, 95%CI: 0.346-0.553,p < .01). Conclusion The present study shows that compliance with guidelines regarding statin initiation during hospitalisation and statin adherence rates during a one-year follow-up period are low for patients treated for ACS. Considering the overwhelming clinical benefits of high-intensity statins in patients with ACS, every effort should be made to increase the rate of optimal use of statins in secondary prevention.