Bismuth sulfide clusters BixSy were produced using a gas-aggregation source and investigated by time-of-flight mass spectrometry following ionization with a 266-nm YAG laser. Stable bismuth sulfide cluster ions Bi4S10+ and Bi6S11+, as well as Bi2S2+, Bi3S2+, Bi2S6+, Bi3S9+, Bi4S7+, and Bi6S4+, were observed, indicative of the production of stable neutral bismuth sulfide clusters in the gas phase. The cluster structure was predicted by density-functional calculations.