Saudi Arabia has seen significant expansion in the delivery of healthcare services during the past twenty years, accompanied by concern about the quality of medical services offered to patients. The Ministry of Interior (MOD healthcare sector meets the needs of MOI employees and their dependants scattered throughout the Kingdom. The Security Forces Hospital (SFH) and General Administration of Medical Services (GAMS) polyclinics are the only two healthcare providers of the free health services in this sector. Pharmaceutical managerial issues focus on ensuring that patients are consistently provided with adequate and sufficient pharmaceutical services delivered in an efficient and effective manner. To maintain provision of pharmaceutical services with high standards, it must undergo periodic systematic evaluation. The aims of this study were, therefore, to examine the quality of pharmaceutical services in MOI healthcare sector, from the perspective of patients, pharmacists and assistant pharmacists, and physicians and nurses in order to identify and develop an understanding of factors that influence their satisfaction level. The study was conducted at the SFH and 16 GAMS polyclinics distributed around the kingdom employing a questionnaire technique, focus group discussions, and interviews. Twelve research questions were used to explore relationships among the study parameters. Data on existing and future situations of pharmaceutical services provision in the MOI healthcare sector were evaluated. Sixteen interviews were undertaken with pharmacy administrative officials in the SFH and GAMS polyclinics for supplementary information to the topic under investigation. Further, data collected from study participants helped to devise a model for optimisation of pharmaceutical services in the MOI. Results showed patients were partly satisfied with current pharmaceutical services provided in the SFH and GAMS polyclinics, and SFH patients were slightly more satisfied than GAMS polyclinics' patients (p 50.001). The healthcare professionals who took part in this study were moderately satisfied with the pharmaceutical services provided. Patients' long waiting time in the Pharmacy Department to obtain their medication and inadequate patient counselling appeared to be important factorsinfluencing patients' satisfaction level in the SFH. Main factors affecting patients' satisfaction level in GAMS polyclinics were poor patient counselling, shortage of medicines, and inadequate facilities. The study results also revealed that elderly, chronically ill patients experienced difficulty obtaining their medication in both settings. However, healthcare professionals indicated the two weakest pharmacy services in both locations were clinical activities and educational programmes. The study also suggested that the absence of a formal drug information centre and electronic database system in GAMS polyclinics affected the professional practice of pharmacy staff. Indeed, findings pointed to advantages to be gained from implementing pharmacy staff motivation policies and procedures. The findings indicate that the MOI healthcare sector provides acceptable pharmaceutical services based on patients' and healthcare professionals' perspectives. In fact there is a need for implementing quality indicators, formal routine inspection and re-organisation of all pharmacy services. Thus, this study has been valuable in identifying the need for optimisation of practice in pharmaceutical services provided by MOI healthcare sector