Background There has been an increasing interest in cluster randomised controlled trial (CRT) over the past 20 years. Little is known about how many CRTs were used by clinical practice guidelines.

Methods We searched National Guideline Clearinghouse (NGC) which is a public resource for evidence-based clinical practice guidelines on December 31, 2012. We selected guidelines which provide MEDLINE full-text linking and then we checked all references cited by those guidelines.

Results We included 564 guidelines and they contained 57495 references. We identified 13 guidelines cited 17 cluster randomised controlled trials as their references. Guidelines are about primary care, cancer, obesity, breastfeeding, cardiovascular and orthopaedics disease. Screening studies accounts for as much as 35% (6) of all CRTs.

Conclusion Cluster randomised controlled trial is considered as the golden standard to assess the effect of intervention in health research. Based on the retrieval strategy study for cluster randomised controlled trial we developed, we estimated that there are about 8000 CRTs in Medline, however, only 17 CRTs were used or cited by clinical practice guidelines, the reasons of low utilisation of CRTs in guidelines are now being investigated and we are going to present the final findings.