<jats:title>Abstract</jats:title><jats:p>The widely used and well‐known bacterial strain <jats:italic>Bacillus subtilis</jats:italic> ATCC 6633 was found to produce two novel, antifungal hydrophilic peptide antibiotics, <jats:sc>L</jats:sc>‐arginyl‐<jats:sc>L</jats:sc>‐2‐amino‐5‐phosphono‐3‐<jats:italic>cis</jats:italic>‐pentenoic acid (<jats:sc>L</jats:sc>‐Arg‐<jats:sc>L</jats:sc>‐APPA, rhizocticin A) and <jats:sc>L</jats:sc>‐valyl‐<jats:sc>L</jats:sc>‐arginyl‐<jats:sc>L</jats:sc>‐2‐amino‐5‐phosphono‐3‐<jats:italic>cis</jats:italic>‐pentenoic acid (<jats:sc>L</jats:sc>‐Val‐<jats:sc>L</jats:sc>‐Arg‐<jats:sc>L</jats:sc>‐APPA, rhizocticin B). Besides rhizocticin A and B, the main components, small amounts of related tripeptides were detected. Instead of the <jats:sc>L</jats:sc>‐Val of rhizocticin B they contain <jats:sc>L</jats:sc>‐Ile or <jats:sc>L</jats:sc>‐Leu and are referred to as rhizocticins C and D, respectively. The C‐terminal residue was identified by NMR spectroscopy as the unsaturated phosphono amino acid <jats:sc>L</jats:sc>‐APPA, known till now only as <jats:sc>D</jats:sc> enantiomer. Enzymatic cleavages of rhizocticin B yielded both <jats:sc>L</jats:sc>‐APPA and rhizocticin A.