Salicylaldehyde 3-oxobutanoylhydrazone (salicylaldehyde acetoacetic acid hydrazone, SAAH) has been used as an analytical reagent for the spectrophotometric determination of molybdenum(vi). The metal ion formed a 1 : 1 greenish-yellow complex with the reagent having absorption maximum at 405 nm, which was. quantitatively extracted into benzene. Under the optimum conditions of the proposed procedure Beer's law was obeyed over the concentration range of 0-18.7 mu g Mo ml(-1). The molar absorptivity and Sandell's sensitivity of the method were found to be 9.96 x 10(3) dm(3) mol(-1) cm(-1) and 0.0096 mu g Mo cm(-2) with a relative standard deviation of +/-0.0025 absorbance units and coefficient of variance as 0.25%, respectively. The proposed method has been applied successfully for micro determination of molybdenum in various alloy steels and a wide variety of synthetic and technical samples with satisfactory results.