Rationale: Helium (He) and energy shortages have dramatically increased prices and reduced their availability of these commodities. The use of three combustion reactions per acquisition of carbon and nitrogen isotope ratios saved 50% He and energy used in elemental analysis/isotope ratio mass spectrometry (EA/IRMS). This approach should be tested for sulfur isotope analyses. Mathods: A method was developed to measure sulfur isotope ratios ( d ³⁴S values) in the SO ₂ produced from three sequential combustion reactions in a single EA/IRMS acquisition. The combustion cycles involved capsules of the same or different materials. Two other developments are presented: a system for simultaneous extraction of chromium-reducible sulfur from four sediments or rock samples and the connections between the SO ₂ reference gas and nitrogen cylinders for purging residual gases at the end of the EA/IRMS sequences. Results: The 3×EA/IRMS- d ³⁴S method was validated with replicate analyses of international reference materials and laboratory standards with a wide range of mineralogical compositions and d ³⁴S values. It was used for d ³⁴S measurements of CRS-pyrites from Archean black shales and Swiss lake sediments. The accuracy and precision of the 3×EA/IRMS values were essentially matched those obtained by conventional EA/IRMS, with good agreement between the mean ± SD values and the recommended values and their Conclusions: Compared with the conventional EA/IRMS method. the proposed method provides accurate and precise sulfur isotope compositions of sulfate and sulfide samples while saving approximately 50% of the He, energy, SO ₂ reference gas, O ₂, and analysis time and cost. Notably, 3×EA/IRMS provided two d ³⁴S values unaffected by potential memory effects.