The nucleotide sequence of 1530 base pairs of Tn10 DNA coding for tetracycline resistance has been determined. The gene start consists of overlapping bidirectional promotors and two operator sequences. One terminator of transcription as defined by the typical terminator sequence is about 1300 base pairs downstream from the promotor. It is preceeded by translation termination codons in all three possible reading frames. The transcript contains an open reading frame coding for a 43.3 kDa protein. Two other possible reading frames are discussed. The amino acid sequence of the Tn10 encoded tetracycline resistance gene shows good homology with two proteins encoded in the tetracycline resistance part of the plasmid pBR322. The hydrophobic nature of the 43.3 kDa protein is discussed with regard to it's proposed function.