The mobile phone is in constant contact with sensitive parts of the body such as the face, ears, nose, lips and hands. Mobile phones provide many necessary environments (temperature, humidity, etc.) for bacteria to grow properly. Microorganisms transmitted over the phone can cause opportunistic infections and chronic diseases, especially in people with suppressed immune systems. In this context, swab samples were taken from the phone cases of the students at our school and planted in petri dishes. Our study has shown that phones, which are among the most used devices during the day, host many microorganisms. Awareness was raised among students by explaining that microbial contamination can be prevented by cleaning phones and phone cases with disinfectants at regular intervals and paying attention to hand hygiene.