Two new cyclodecapeptides, atratumycins B (<b>1</b>) and C (<b>2</b>), containing substituted cinnamoyl side chains were generated by converging elements of the atratumycin (<b>3</b>) and atrovimycin (<b>4</b>) biosynthetic pathways. The structures of <b>1</b> and <b>2</b> were determined on the basis of HRESIMS, 1D and 2D NMR data, and X-ray single-crystal diffraction studies. Atratumycin B (<b>1</b>) is active against autoluminescent <i>Mycobacterium tuberculosis</i> H37Rv, displaying a minimum inhibitory concentration of 3.1 μg/mL (2.3 μM).