In the course of screening for new anticancer antibiotics from myxobacteria, strain JW357 was found to produce an antibiotic that was active against several human cancer cell lines. This strain was identified as Angiacaccus disciformis by morphological and cultural characteristics. The antibiotic produced was identified as myxochelin A. It demonstrated significant cytotoxicity against certain human cancer cells with $IC_{50}$ values ranging 1.15 to $2.36{mu}g/ml$. Myxochelin A was interestingly as active against multidrug-resistant CL02 cells as against the sensitive parental cells (HCT15).