Abstract: The present invention relates to a method and a kit for diagnosis of semen quality (motility and concentration) through observation of color change visible with the naked eye in a solution combining methylene blue and sperm. The invention comprises a method for semen diagnosis using color coding (with a standard color table) charting the various colors the semen may change into, and a diagnostic it for testing semen using said method. When combined with methylene blue, healthier and more active sperm fades the original blue color more rapidly due to respiration activity by the sperm, which allows for semen quality evaluation. The above principle are adapted to kit from inside a tube which encases a methylene blue solution into which sample semen is introduced for easy evaluation.