We report NMR- and MS-based structural characterizations of siderophores and related compounds from <i>Beauveria bassiana</i> (Balsamo-Crivelli) Vuillemin, including ten new chemical entities (<b>2</b>-<b>4</b>, <b>6</b>-<b>9</b>, <b>11</b>-<b>12</b>, and <b>15</b>) and five known compounds, (<b>1</b>, <b>5</b>, <b>10</b>, <b>13</b>, and <b>14</b>). The siderophore mixture from ARSEF strain #2680 included two compounds in which <i>N</i><sup>5</sup>-mevalonyl-<i>N</i><sup>5</sup>-hydroxyornithine replaces both (<b>2</b>) or one (<b>3</b>) of the <i>N</i><sup>5</sup>-anhydromevalonyl-<i>N</i><sup>5</sup>-hydroxyornithine units of dimerumic acid (<b>1</b>). Mevalonolactone (<b>14</b>) was present as a degradation product of <b>2</b> and <b>3</b>. ARSEF #2860 also produced compounds that have mannopyranose (<b>5, 6</b>) or 4-<i>O</i>-methyl-mannopyranose units (<b>4</b>, <b>7</b>), two compounds (<b>8</b>, <b>9</b>) that can be rationalized as 4-<i>O</i>-methyl-mannopyranosyl analogues of the esterifying acid moieties of metachelins A and B, respectively, and two probable decomposition products of <b>1</b>, a nitro compound (<b>11</b>) and a formate (<b>12</b>). Beauverichelin A (<b>15</b>), a coprogen-type siderophore that represents the di-4-<i>O</i>-methyl-mannopyranosyl analogue of metachelin A, was detected in crude extracts of ARSEF #2860, but only in trace amounts. ARSEF strains #252 and #1955 yielded beauverichelin A in quantities that were sufficient for NMR analysis. Only the di- (<b>1</b>-<b>7</b>) and trihydroxamate (<b>15</b>) siderophores showed iron-binding activity in the CAS assay and, when ferrated, showed strong ESIMS signals consistent with 1:1 ligand/iron complexes.