In the Mexico earthquake of September 19, 1985, many reinforced concrete (RC) buildings of medium height in Mexico City were severely damaged. Understanding the cause of the damage is useful for future design of earthquake-resistant RC buildings. Many factors contributed to the damage. The number of stories of the buildings and the property of soil conditions etc. can be considered to be some of them. Therefore, investigation of the relationship between the damage rank of the building and the number of stories of the buildings and that between damage rank and the property of soil conditions are important in determining the cause of the damage. From the above view point, the Architectural Institute of Japan (AIJ) measured the structural damage ranking (degree of damage) of 3821 damaged and undamaged RC buildings in Mexico City. This paper is a report on the results of the statistical research of the relationship between the number of stories of the building, the property of the soil condition and the damage rank of the building for 3 821 RC buildings. The conclusions of the statistical research are shown below. 1) The closest relation was observed between damage rank of buildings and the number of stories. Also, damage rank (major damage, collapse) with increase of building height increases. And maximum story number of damaged buildings was 9 story building. 2) The same can be said for property of soil conditions. The building damages at Hill Zone (firm ground zone) were slight, but the damages at Lake Zone (soft soil zone) were severe. This is in agreement with the theoretical results of established response analysis.