This paper describes a method for the preparation of 125I brachytherapy sources. The process consist of surface oxidation of a silver rods [0.5 mm (ϕ) × 3 mm (1)], formation of a thin silver bromide over layer and finally replacement of bromide ions by 125I− ions. The effect of various parameters such as 125I feed activity, iodide carrier concentration and reaction time were examined and optimized for maximum impregnation of 125I activity on the substrate. Sources containing 74–111 MBq (2–3 mCi) 125I on a silver matrix could be prepared and encapsulated in titanium capsules [0.8 mm (ϕ) × 4.75 mm (1)] using Nd: YAG laser. Quality assurance tests to ensure nonleachability, uniform distribution of activity and leak tightness that are necessary before application were evaluated.