Sterilization and disinfection are important methods used to control microorganisms and prevent the spread of infectious diseases. These processes are widely used in hospitals, laboratories, food industries, and homes to maintain hygiene and protect public health. Sterilization is the complete destruction of all microorganisms including bacteria, viruses, fungi, and spores. Common sterilization methods include heat, steam under pressure, radiation, and chemicals. Autoclaves are commonly used in hospitals to sterilize surgical instruments using high-pressure steam. Disinfection reduces or kills harmful microorganisms but may not destroy all spores. Disinfectants are chemicals applied to surfaces, instruments, and objects. Common disinfectants include alcohol, chlorine, and hydrogen peroxide. Heat is one of the oldest and most effective sterilization methods. Boiling water can kill many microorganisms, while dry heat and steam are used for medical equipment. Filtration is another method used to remove microorganisms from liquids and air. Proper sterilization and disinfection are essential in healthcare settings to prevent hospital-acquired infections. Medical workers must follow hygiene procedures carefully to protect patients and staff. In homes, cleaning kitchens, bathrooms, and frequently touched surfaces helps reduce microbial spread. Hand washing remains one of the simplest and most effective methods of preventing infection. Scientists continue developing safer and more effective sterilization technologies to improve infection control and public health. Al-Mustaqbal University – the first university in Iraq.