In the present work a computer analysis of deletion localization in the sequence of the E. coli lacI gene has been carried out by the statistical weight method. Reliable statistical correlation of the deletions location sites with the arrangement of the most perfect direct repeats revealing the shortest distance between repeated fragments has been shown. At the same time statistical analysis did not reveal reliable connection of deletions localization regions with the expected sites of gyrase recognition, sites and other recombination sites. A conclusion has been drawn, that the mechanism of deletions emergence on the basis of repeats appears to be predominant.