A population's age and sex composition is the foundation of demographic analysis. Recent Indonesian censuses and surveys indicate widespread ignorance about ages. This research note investigates the quality of the 1985 intercensal survey, called by its Indonesian acronym SUPAS 85. The age and sex data published in the final reports are compared to the 1971 and 1980 censuses to determine if the survey represents an improvement or a deterioration in data collection and to analyze the consistency of the findings. Hopefully this will serve as an aid to interpreting contemporary demographic trends. This research note highlights particular patterns common throughout Indonesia and brings attention to specific provinces with extremely irregular age and sex ratios. Whether it is through census survival rates, age or sex ratios, anyone interested in Indonesian demographic trends needs to be aware of errors in age statements and their pattern by age and sex.