This paper presents a simple, rapid, and accurate voltammetric method for determination of boron in water and steel samples using a disposable pencil graphite electrode. The oxidation of Tiron in the boron Tiron complex in phosphate buffer at pH 7.5 was measured as a response. Type and concentration of supporting electrolyte, pH, ionic strength, Tiron concentration, scan rate, step amplitude, pulse amplitude, and pencil grade were investigated as the parameters affecting the peak current. The limit of detection (3s) was estimated as 84 mu g/L. The relative standard deviation of the method was 4.6 for 1 mg B/L (N = 7). The recovery results varied between 90% and 103% for water samples and between 94% and 108% for steel samples. The results were compared with those obtained from the ICP-OES method and no statistically significant difference between the methods was found.