During the last decade many countries have become increasingly interested in the development and use of evidence-based practice guidelines, recognising that guidelines are key tools to improve the quality and appropriateness of health care. They are considered to be the ideal mediator for bridging the gap between the growing stream of research findings and actual clinical practice. Systematic reviews of guideline evaluations have shown that clinical practice guidelines can be an effective means of both changing the process of healthcare delivery and improving outcomes. A review of 59 guideline evaluation studies found that, in all but 4, statistically significant improvements occurred in clinical practice after implementation [17]. A systematic review of 87 studies on the use of guidelines concluded that 81 studies revealed evidence of improved patient outcomes [12]. Evidence-based guidelines are becoming an important and indispensable part of quality healthcare because of their potentials to improve quality and also reduce cost of health-care. Adherence to guidelines and protocols may reduce health-care costs up to a 25% [11]. We will present an overview of the history of guidelinedevelopment and give some widely used definitions of guidelines. Guidelines are developed in a structured and systematic way, this process will be explained later. Also implementation tools necessary to put the guidelines into practice in an active way, will be discussed.