The Lothian Birth Cohort 1936 sample is in a uniquely good position to provide relevant data on social class mobility patterns over most of the last century. These participants, with known ultimate social class attainment, took a validated mental test in the Scottish Mental Survey of 1947 and were followed up at approximately age 70. Then, besides their own age 11 mental ability data and educational and occupational attainment, they reported educational and occupational data on their parents and offspring. We constructed structural equation models of participant and offspring social class attainment and odds of social class movement, and compared results with those from the similarly recruited and assessed Lothian Birth Cohort 1921. In the 1936 cohort, relative transmission of social class from one generation to the next decreased, while relative transmission of educational attainment increased. In addition, effects of childhood IQ and educational attainment on social class decreased, apparently due to relative decrease in overall upward mobility and absolute increase in overall education level. (Contains 10 tables and 1 figure.)