Molybdenum blue was electrodeposited on a pencil graphite electrode (PGE) by cyclic voltammetry and it was used in the detection of phosphate ions for the first time in the literature. Polyvinyl chloride was used as a coating agent for the modified electrodes to improve their stability. The characterization of the electrodes was done by using microscopic and electrochemical methods. Parameters affecting the analytical response of the electrode in differential pulse voltammetry such as concentration of supporting electrolyte, immersion time, operation temperature and thickness of film were optimized before the analysis of a soil sample containing phosphate. The prepared electrode exhibited high sensitivity for phosphate. The limit of detection (LOD) and limit of quantification (LOQ) were determined as 2.19 x 10(-8) M (S/N = 3) and 7.30 x 10(-8) M (S/N = 10), respectively. Quantification of phosphate in soil samples was confirmed by spectroscopic analysis.