New, simple and rapid spectrophotometric methods were described for the micro-determination of some rare earth metal ions uranium(VI), samarium(III) and cerium(III) using a new synthesized sulfacetamide azo dye derivative [2-((4-(N-ace-tylsulfamoyl)phenyl)diazenyl)-3,4,5-trihydroxybenzoic acid] (APDB). The new reagent was reacted with the three rare earth metal ions forming colored complexes at 500, 535 and 540 nm for U(VI), Sm(III) and Ce(III), respectively. The complexes were formed in alkaline medium using borate bufer at pH = 9 for U(VI) and Sm(III) and at pH = 8 for Ce(III). The absorb-ance of U(VI) and Sm(III)-APDB complexes was enhanced in the presence of CTAB as a cationic micellar media while that of Ce(III)-APDB complex was improved by using aerosol GPG surfactant. The proposed methods were also improved by using acetone and DMF as organic solvents for only U(VI) and Sm(III)-APDB complexes, respectively. The three metal ions complexes were formed by 1:2 (metal:ligand) ratio. Beer’s law was followed over the concentration range of 5–80, 10–160 and 10–80 µg mL −1 for U(VI), Sm(III) and Ce(III), respectively. The proposed methods showed 0.8910, 2.454 and 2.750 µg mL −1 limit of detection and 2.700, 7.436 and 8.335 µg mL −1 quantifcation limit (LOQ) for U(VI), Sm(III) and Ce(III) complexes, respectively. The relative standard deviation was also calculated to be 0.00899, 0.00461 and 0.0180 for U(VI), Sm(III) and Ce(III) complexes, respectively. The interference efect of various diverse ions was also investigated. The proposed methods were successfully applied for the determination micro-amounts of the selected metal ions in some industrial, biological and plant samples.