In the growing world of technology, cellular devices have quickly emerged as one of the fastest evolvingrnfields. They have increased greatly in both popularity and complexity, requiring more advancedrnoperating systems and applications to meet the demands of the user. Android is a software stackrndesigned to meet these demands in an open source environment. It includes an operating system,rnmiddleware, and key applications, as well as a Software Development Kit (SDK) for developers torncreate their own applications for the Android environment.rnThis project is targeted to develop a perpetual Ethiopian and Gregorian calendar system andrnorganizer application that runs on the top of Android mobile phones. Perpetual calendars provide arndate over a wide range of years. This project came up with the Ethiopian calendar system with therncorresponding Gregorian calendar of any year. The calendar provides the date of the public holidays ofrnNational (non religious), Christian and Muslim holidays of any month and year the user prefers tornknow. In addition to this users are supported to organize their tasks based on the Ethiopian calendarrnfor a specific period of time with Ethiopic script. Once the task is organized or scheduled the users arernalarmed when the time of the schedule reached. Besides these, users are supported to keep diaries atrnany specific date of Ethiopian calendar using Ethiopian scripts. Lastly the system has been tested andrnthe result shows that it works correctly 100%.rnKeywords: Perpetual Ethiopian calendar, Ethiopian calendar, Ethiopian and Gregorian calendar,rnEthiopic Organizer, Ethiopic Diary, Ethiopic Calendar on Android