The ultimate goal in dermatological therapy is to use the safest and least number of drugs in order to obtain the best possible effect in the shortest period and at reasonable cost. Rational drug use (RDU) is conventionally defined as the use of an appropriate, efficacious, safe and cost-effective drug given for the right indications in the right dose and formulation, at right time intervals. WHO estimates that more than half of all medicines are prescribed, dispensed or sold inappropriately, and that half of all patients fail to take them correctly as prescribed by the doctor. The process of Rational prescription for a Dermatologist (RPD) involves a series of steps such as defining the patient's illness, specifying the treatment objectives, using the principle of P-treatment, starting the treatment, providing appropriate information and monitoring the treatment. Reasons for irrational prescription could be physician related, patient related, industry related, regulations related. Practicing medicine irrationally can lead to disastrous events like increased morbidity and mortality, drain of resources, drug resistance etc. Principles to enhance the RDU in our practice and minimize errors of prescription are discussed in detail in this article.