This paper presents a revised Fixed-base model (RFBM) for the estimation of adult mortality in developing countries. The RFBM also derives estimates of adult mortality from the age distributions of two censuses by 5-year age-groups. Unlike the original version, RFBM does not depend on person – years lived between exact ages 0 and 5 years  ( 5L0 ) and the mid-point population of those aged 0 – 4 years  ( 5N0 ) . Both 5L0 and  5N0 are known to be affected by under-reporting in most developing countries. The estimates of the RFBM appear to have improved and compare favourably with estimates from other methods. We recommend the use of the model, especially when there is insufficient data for direct estimation of adult mortality in developing countries, among others.