Radwan M, et al. – The intent of this research was to determine the predominant culture within the Palestinian Primary Healthcare Centers of the Ministry of Health (PHC–MoH) and the Primary Healthcare Centers of the United Nations Relief and Works Agency for Palestine Refugees (PHC–UNRWA) by using the competing values framework (CVF). Furthermore, an inspection was carried out of its effect on the adherence to the Clinical Practice Guideline (CPG) for diabetes mellitus (DM). The organizational culture displayed a marginal influence on the adherence to the diabetic guideline. Prospective studies ought to combine quantitative and qualitative approaches and analyze the utility of more sensitive instruments to estimate such a complex construct and its effects on guideline adherence, in small–sized clinics.