A procedure for the rapid isolation of DNA from the yeast Saccharomyces cerevisiae is described. To release plasmid DNA for the transformation of Escherichia coli, cells are subjected to vortex mixing in the presence of acid-washed glass beads, Triton X-100, sodium dodecyl sulfate, phenol and chloroform. Centrifugation of this mixture separates the DNA from cellular debris. E. coli can be efficiently transformed with plasmid present in the aqueous layer without further purification of the plasmid DNA. This procedure also releases chromosomal DNA. Following two ethanol precipitations, the chromosomal DNA can be digested by restriction endonucleases and analysed by Southern blot analysis.