The cells of Bacillus subtilis, grown in minimal media, are known to become competent for transformation for a short period at a specific phase of ceil growth. In the present work the cells (strain 168 ind−) were grown in continuous culture (chemostat; glucose limiting, generation time 4 h, 37 °C). Aliquots were removed at 20- to 24-h intervals and immediately tested for competence. The viability (41 h) was 97%. The initial very low competence increased up to 200-fold within the 24 h and remained at this high, slowly decreasing level for at least 168 h. It is concluded that a long-lasting competence may develop and persist in the cells in continuous culture ("steady-state"), without demonstrable harmful effects to the population.