A randomized controlled trial (RCT) is a prospective, comparative, quantitative experiment/study that is performed under controlled conditions with random allocation of interventions to comparison groups. Among all the clinical study designs, evidence generated from RCTs is considered to be at top of the evidence pyramid. There are many different RCT designs and they can be classified on the basis of interventions evaluated, participants’ exposure and level of blinding. All RCTs should be planned prospectively, a research question should be formulated, sample population approached and informed consent obtained from participants of the trial. These consented subjects are randomly assigned to any of the study arms and the changes are then measured over time. The basic principles to designing an RCT include formulating a research question, developing a protocol, randomization, allocation concealment, blinding, sample size calculation and registering of RCTs. Appropriate guidelines for reporting RCTs should be followed and RCTs should only be conducted if they are ethically viable, economical and clinically worthwhile. Keywords: Randomised Control Trial (RCT)