Objectives: To study the Drug Information Service (DIS) awareness program organized by a DIS unit in Malaysian hospital through utilization of provided services by the healthcare professionals, allied healthcare providers, patients and the public, and to identify the characteristics of inquiries received. Materials and Methods: An awareness program to promote the services of the DIS unit was held throughout the month of March in 2010. Drug information queries forms that have been documented six months prior to (September 2009–February 2010) and six months after (April–September 2010) the awareness program were collected and assessed. Mean monthly inquiries volumes pre- and post-program were compared to evaluate the effectiveness of the program. Types of information requestors, inquiries, reference sources, and drug class information were identified and evaluated. Results: A total of 747 drug information queries forms were received during the study period. The mean total utilization of the DIS unit services after (63.67 ± 18.24) the DIS awareness program was increased but not significant (P < 0.05) when compared to records before (60.83 ± 21.49) the program. Majority of the DIS service users were the pharmacist (67.5%), followed by the doctors (24.9%). Most inquiries were regarding the dosage and route of administration of drugs (61.4%). The most frequently referred sources of information were the Micromedex and the Internet (37.3%). The most common inquiries were related to the anti-infective agents (37.8%). Conclusion: Provision of sufficient and accurate drug information to the healthcare professionals, patients, and the public is crucial to ensure optimization of therapy. The utilization of services provided by the DIS unit should be supported. Frequent DIS awareness program should be undertaken to promote and encourage the use of services.