The odd-numbered symphonies of Ludwig van Beethoven have long been said to differ qualitatively from his even-numbered symphonies. Yet, no quantitative study has determined whether this common assertion has any empirical justification. In the current investigation, his nine symphonies were assessed on 10 potential correlates: prominence, popularity, aesthetics, accessibility, length, the number of themes, and four computer content analytical measures associated with melodic originality (mean, standard deviation, maximum, and minimum). The odd-numbered symphonies were distinguishable from the even-numbered symphonies in prominence as well as three out of the four content analytical measures. Moreover, the prominence of his symphonies was strongly correlated with the three melodic originality indicators. Given that the computer analyses cannot have been contaminated by subjective biases, the odd versus even distinction has been empirically confirmed. The article closes with a discussion of what the empirical results may imply about Beethoven's creative process.