SIGMA, JURNAL SAINS DAN TEKNOLOGI, Vol. 13, No. 1 Januari 2010, ABSTRAK : Measurement mostly required a precision, accurary, and sensitivity.Measurement by using the analog altimeter often shows that the obtained data are inaccurate, because lot of error factor influencing the meansurement. To reduce the error factor, the altimeter is made digitally. Digital altimer based on microcontroller AT89S53 is a measuring device that is designed to measure relative or absolute altitude. This measuring instrument can be realized by using the atmospheric pressure sensor type MPX4100, voltage divider circuit, ADC 16 bits type AD7715 with serial control, microcontroller AT89S53, and LCD. The place for retrieving altitude data are selected randomly. From the result of testing and analyzing, this device produced the altitude measurement with average level of measurement error kurang lebih dari 0,367%, average value level of measurement accuracy is equel to 99,6%, and the average of deviation kurang lebih dari 1,4 m at interval 100 m - 1180 m.