Objective To describe the secondary preventive measures adopted in the management of patients with Acute Coronary Syndrome (ACS) admitted to the National Hospital of Sri Lanka (NHSL), in comparison with standard guidelines. Methods A hospital based, descriptive cross-sectional study was carried out in the Cardiology Unit and medical wards of the NHSL during September to October 2009. A sample of 345 patients diagnosed with ACS was included in the study. Medical records were used as the source of data regarding secondary preventive measures during the inward period. Results Among ACS recruited, 168 (48.7%) were diagnosed with unstable angina, 92 (26.7%) with NSTEMI and 85 (24.6%) with STEMI. Acetyl Salicylic Acid (ASA) was given within 3 hours and documented in only 175 (53.7%). Although a twelve-lead ECG within 20 minutes of arrival at hospital is recommended in the guidelines, ECG was performed after 20 minutes in 203 (59%). In 85 with STEMI 66 (77.6%) received re-perfusion/streptokinase therapy. The time of commencing streptokinase was noted in only 49 (57.6%) and only 9 (18%) received streptokinase within 30 minutes of arrival in hospital. Left ventricular function was assessed in only 53 (15.4%) patients. Continuity of treatment with ACE inhibitors was seen in 298 (86.4%), beta-blockers in 213 (61.7%) and statins in 326 (94.5%). In 337 (97.7%) a maintenance dose of ASA was given during the hospital stay. Conclusions Some processes in the management of patients with ACS at NHSL did not meet the standard set by local and international guidelines on secondary preventive measures.