Method for cryopreservation of human spermatozoa free from seminal plasma using a fast and simple aseptic vitrification-devitrification process, said method comprising: (a) providing spermatozoa free from seminal liquid; (b) resuspending and mixing the spermatozoa obtained in step (a) in a 1:1 volumetric ratio with a vitrification medium comprising: i) buffering medium for spermatozoa, ii) a non-permeable cryoprotectant with a final concentration of 0.15 to 0.30 M, and iii) a dextran supplemented serum; (c) mixing and adjusting the final concentration of spermatozoa within a range from 0.2 × 10 6 to 1.8 × 10 6 spermatozoa per 100 μl of said vitrification medium; (d) placing 100 μl of the mixture of spermatozoa and vitrification medium immediately after step (c) in a 0.25 ml straw leaving 1 cm free of liquid at both ends, this first straw placed inside a second 0.5 ml straw to be sealed at both ends, the first and second straws being placed horizontally in a thermoconductor receptacle; (e) immersing the 0.5 ml straw resulting from step d) with the sperm content in horizontal position in liquid N 2; (f) keeping the sperm sample inside the straws at a temperature between - 75°C and -85°C; (g) devitrifying the sample by introducing the straw containing the sperm sample in a devitrification medium comprising: i) buffering medium for spermatozoa, ii) Human Tubal Fluid supplemented with 1% w/v Bovine Serum Albumine, and iii) a serum supplemented with dextran; wherein devitrification is carried out first by placing the samples to be devitrified in a container with liquid N 2 and then introducing three 0.25 ml straws with sample in a tube with 5 ml of devitrification medium incubated at a temperature ranging from 36.5 to 37.5°C in a heating block. (a) providing spermatozoa free from seminal liquid; (b) resuspending and mixing the spermatozoa obtained in step (a) in a 1:1 volumetric ratio with a vitrification medium comprising: i) buffering medium for spermatozoa, ii) a non-permeable cryoprotectant with a final concentration of 0.15 to 0.30 M, and iii) a dextran supplemented serum; i) buffering medium for spermatozoa, ii) a non-permeable cryoprotectant with a final concentration of 0.15 to 0.30 M, and iii) a dextran supplemented serum; (c) mixing and adjusting the final concentration of spermatozoa within a range from 0.2 × 10 6 to 1.8 × 10 6 spermatozoa per 100 μl of said vitrification medium; (d) placing 100 μl of the mixture of spermatozoa and vitrification medium immediately after step (c) in a 0.25 ml straw leaving 1 cm free of liquid at both ends, this first straw placed inside a second 0.5 ml straw to be sealed at both ends, the first and second straws being placed horizontally in a thermoconductor receptacle; (e) immersing the 0.5 ml straw resulting from step d) with the sperm content in horizontal position in liquid N 2; (f) keeping the sperm sample inside the straws at a temperature between - 75°C and -85°C; (g) devitrifying the sample by introducing the straw containing the sperm sample in a devitrification medium comprising: i) buffering medium for spermatozoa, ii) Human Tubal Fluid supplemented with 1% w/v Bovine Serum Albumine, and iii) a serum supplemented with dextran; wherein devitrification is carried out first by placing the samples to be devitrified in a container with liquid N 2 and then introducing three 0.25 ml straws with sample in a tube with 5 ml of devitrification medium incubated at a temperature ranging from 36.5 to 37.5°C in a heating block. i) buffering medium for spermatozoa, ii) Human Tubal Fluid supplemented with 1% w/v Bovine Serum Albumine, and iii) a serum supplemented with dextran;