A number of boron, phosphorus, and arsenic compounds, viz., B2H6, B10H14, B3N3H6, B2S3, BF3, BCl3, BBr3, BI3, HBO2, P, PH3, PF3, PF5, PCl3, POCl3, P2O5, As, AsH3, AsF3, AsCl3, and As2O5, are compared as sources of boron, phosphorus, and arsenic ion beams in a hot‐filament electron‐impact or oscillating‐electron‐discharge (OED) ion source. Performance comparison data, including the percentage of B+, P+, P2+, P+2, As+, As2+ and As+2 in the total beam and the maximum ion currents observed at the target of a 150‐kV ion implantation system, are given for a common set of source and system conditions. BF3 and BCl3 are evaluated as the first and second best materials for B+, with any other compound providing only a poor third choice. The pure elements P and As provide large currents of both monatomic and diatomic ions and have no other interfering ion components. PH3 is a good source of P+ but has strong nearby hydride ions. The fluorides of P and As provide good currents of monatomic ions and have proved convenient to use.