ICU patients are at high risk of drug-drug interactions. In Middle East there is no sufficient data about the incidence of drug interactions. To explore the frequency and pattern of potential drug-drug interactions (PDDIs)and to study the impact of clinical pharmacist educational intervention on the (PDDIs) in surgical intensive care unit. A three phases study,phase (1) (pre-intervention phase)wasaretrospective cohort study of the frequency of potential DDIsin 500 prescriptions of patients in surgical ICU using Lexi-Interact interaction database. Phase (2) (intervention phase) involved the implementation of DDIs reducing measures. Phase 3 (post-intervention phase) was a prospective study of the frequency of potential DDIs in the 500 prescription collected after intervention phase (phase 2). A total of 2228 PDDIs were identified during phase 1 and 2139 PDDIs were identified during phase 3. In both phases most of the PDDIs encountered were of ‘Moderate’ severity (89%) of the PDDIs during the pre-intervention phase and 91.5% during the post-intervention phase were of risk rating C. There was no statistical difference between mean number of PDDIs in pre-intervention and post-intervention phases (P=0.859). There was no statistical difference in percent of PDDIs in the different degrees of severity between pre-intervention and post-intervention phase (Z=-1.4, P= 0.153). The present study demonstrated a relatively high frequency of occurrence of PDDIs among patients in surgical ICU. However, most of them were of minor-to-moderate clinical significance.