Numerous types of extended surfaces have been used in the past but those with finned pins have proved to be unique in increasing the rate of heat transfer. Hsieh working on the original idea ot professor Hsu proved that heat transfer rate can be further increased by putting annular fins on a pin. In this thesis the design of finned pin was optimized to give maximum heat transfer rate from a given primary surface, and an experimental investigation was conducted to verify the results. 1. Theoretical Investigation consists of: (1) Reproduction of mathematical equations for pin and finned pin (2) Study of heat transfer characteristics of pin and finned pin. (3) Optimization of the design of pin and finned pin. (4) Sample calculations of heat flow rate for pin and finned pin. 2. Experimental investigation consists of: (1) Construction of finned pin, pin and primary surfaces. (2) Set-up of experimental equipment. (3) Comparison of heat flow rate for finned pin, pin and plate. 3. Conclusions: The conclusions were based on tile comparison of finned pin. and pin. The heat transfer rate from 8" x 4 ½” surface was increased by employing finned pin. The maximum increase was 36%. / Master of Science