The difficulty level of college courses has been identified as a value which varies across courses. A sample of fifty (50) introductory-level college courses was selected and four different measures of course difficulty, (1) perceived difficulty, (2) perceived amount of work, (3) average grade awarded, and (4) average ACT composite of enrolled students, were calculated for each course. The difficulty estimates were examined for consistency for each measure individually, over time, and in comparison with the others. Correlation analysis, multiple regression, factor analysis, hierarchical cluster analysis, and analysis of variance procedures were used. The four measures were combined into one composite index of course difficulty and the resulting estimates were used to improve the prediction of academic achievement.