This thesis presents the results of six series of tests in which bond behaviour of uncoated and fusion bonded epoxy coated reinforcement were compared. In order to investigate the influence of rib geometry of teh bar on bond performance, teh tests were donducauted on bars with various rib geometries. variations in rib geometry were obtained from production bar samples obtained from different sources, and also from machined bars manufactured and coated in the laboratory. various test methods were employed to examine the incluence of test methods on relative bond perfromance. Mode of bond failure, bond/slip characteristics and ultimate bond sterngth and crack control characteristics were measured. Results of the experimental investigation indicate that bond test methods which resulted in splitting failures of teh concrete cover give bond stress values of the same order as the allowable values in BS 8110. It was found that the present BS 8110 design ond stresses do not provide adequate margin of safety for use with epoxy coated bar, despite the ability of these bars to meet the BS 4449 requirements for classification as type 2 deformed bars. It was found that, for both coated and uncoated reinforcement, bars with increased bond strength.it is demosntrated that epoxy coated bars with improved rib face angle and relative rib area appear capable of dvedeveloping the same design bond strengths as uncoated bars with an adequatemargin of safety provided certain mainmum requirements are met. Proposals are made for this required rib geometry and for an alternative of a reduction factor for bond stresses with existing rib geometrics. A theoretical analysis of bond strength of deformed bars is also presented. the analysis shows that bond strength of deformed bars is strongly influenced by their rib goemetrics and surface conditions. Analysis of the results for the appropriate specimens show good aggreement with experimental results.