In an experiment aimed at assessing dimensional properties of musical space, musicians rated the similarity of pairs of brief melodies on a 9-point scale. From our review of previous work, we hypothesized (1) that pitch variables would be considered more important than time or rhythmic variables by our subjects and (2) that the metrical consonance of pitch and duration patterns would generate a factor related to pattern regularity in listeners' musical space. Four melodies and their inversions were played in each of four rhythmic patterns (anapestic, dactylic, iambic, and trochaic) for a total of 1024 pattern pairs. Both multidimensional scaling and cluster analyses of similarity showed that at least five dimensions were needed for a good accounting of the perceptual space of these melodies. Surprisingly, the major dimensions found were rhythmic: (1) duple or triple rhythm, (2) accent first or last, and (3) iambic-dactylic versus trochaic-anapestic. Other dimensions were (4) rising or falling pitch and (5) the number of pitch—contour inflections. The tendency to rate patterns on the basis of time or rhythm (Dimensions I, II, and III) was negatively correlated with the tendency to rate patterns on the basis of pitch (Dimensions IV and V). It could not be determined whether this result depends on cognitive processing limitations, attention, or preferences. No factor was found that related to pattern regularity as we defined it.