Clin. pharmacol. studies are one of the most interesting clin. studies conducted during the clin. development of any new pharmaceutical product. Depending upon the pharmacol. or therapeutic class of the product, it mainly involves different kinds of phase 1 studies. Clin. pharmacol. studies are very specialized studies and are conducted with specific objectives to understand safety, tolerability, pharmacokinetics and / or pharmacodynamics of the drug. Not only designing of such studies, but conducting, analyzing and interpreting results of such studies are challenging. Designing such studies requires understanding of basic and clin. pharmacol. as well as understanding of feasibility of conducting the studies. Conducting such studies requires knowledge and clin. skills. Bioanal. knowledge and skills are required for bioanal. in order to estimate the drug and / or metabolites of interest. For data anal. and interpretation; knowledge of pharmacokinetics, pharmacodynamics and biostatistics is required. Thus, such studies involve team of scientists from different disciplines including basic and clin. pharmacologists, clinicians, medical emergency experts, bioanal. experts and statisticians. Results of such studies creates excellent base for phase 2 proof of concept studies. Some of these studies are also conducted in parallel or after phase 2 or phase 3 studies to address specific need. In this article, authors have summarized various clin. pharmacol. studies with their basic principles and key objectives.