In two experiments, descriptions of melodic contour structure and predictions of perceived similarity relations between pairs of contours produced by a number of different models are examined. Two of these models, based on the music- theoretic approaches of Friedmann (1985) and Marvin and Laprade (1987), characterize contours in terms of interval content or contour subset information. The remaining two approaches quantify the global shape of the contours, through the presence of cyclical information (assessed via Fourier analysis) and the amount of oscillation (e. g., reversals in direction, pitch deviations) in the contours. Theoretical predictions for contour similarity generated by these models were examined for 20th century, nontonal melodies (Experiment 1) and simplistic, tonal patterns (Experiment 2). These experiments demonstrated that similarity based on Fourier analysis procedures and oscillation measures predicted a derived measure of perceived similarity, with both variables contributing relatively independently; the music- theoretic models were inconsistent in their predictive power. These results suggest that listeners are sensitive to the presence of global shape information in melodic contour, with such information underlying the perception of contour structure and contour similarity.