Abstract: In prokaryotes are known two kinds of transcription terminators that are distinguished by their mechanisms and DNA sequences. When RNA polymerase encounters an intrinsic terminator (RIT), it can release the nascent RNA spontaneously, but when it encounters a Rho dependent terminator (RDT), the release of the RNA depends on the action of a protein factor called Rho. RDT are involved in the gene expression as attenuators in the leader or intra operon and as terminators at the end of operons. A RDT consists of three distinct parts, which together extend over 150-200bp of DNA (figure 1). The upstream part, called the Rho utilization (rut) site, encodes a segment of the nascent transcript to which Rho can bind and is essential for starting termination. The central part, that we called Rho activity (rac) sequence, is the second mRNA binding site to which Rho can bind and is essential for helicase/traslocation activity. The downstream part, called the transcription stop point (tsp) region, is where RNA polymerase pauses during elongation in the absence of Rho. In the literature is present only a small number of studies of single RDT, very little is know about their structure and sequence and is not existing any in silico predictive method.