A method based on the treatment of akinetes using diluted solutions of sodium hypochlorite (SH solution) was developed to obtain axenic cultures of Nostoc strains (Nostoc Vaucher ex Bornet & Flahault, 1886:181). Three strains were independently grown on liquid BG-110 medium (BG-11 without a nitrogen source) until a massive differentiation of akinete cells took place. Samples of these akinete-rich cultures were homogenized and treated with diluted SH solutions (1, 2, and 3 %) for 10, 20, and 30 s. Subsequently, the treated akinetes were spread onto BG-110-agar plates and incubated under standard conditions for at least 2 weeks. Both the axenicity and the degree of contamination were monitored for each treatment by inoculating spring colonies in nutrient-broth or R2A-agar plates. Axenic cultures were obtained for the strains Nostoc sp. CCLFM I (with 1 % SH solution), Nostoc sp. CCLFM VIII (2 and 3 %) and Nostoc sp. CCLFM XXI (3 %), only applying 10 s of treatment exposure. This strategy was proven to be efficient for Nostoc cultures, as all of the tested strains became axenic. This method can be applied to virtually any strains that are capable of performing massive akinete differentiation; furthermore, it is a fast, inexpensive, and antibiotic-free approach.