The purpose of this experiment was to plot equal pitch‐modulation contours as statistical functions of duration, direction, and extent of frequency modulation. Twenty college students listened to 66 quasipure tones each of which was a combination of one of six durations (40–1000 msec) and one of 11 extents of modulation (−10 to +10 semitones). Duration and direction as well as extent of frequency modulation affected pitch modulation as evaluated by a method of magnitude estimation. A regression line was fitted to the listeners' responses plotted on a coordinate of pitch modulation (psychological) and frequency modulation (physical) for each combination of duration and direction. Expected mean values on the regression lines rather than the actual mean values were used to plot the contours for each extent, duration, and direction. The nearest but significantly different mean values from the expected mean of zero were used to determine the thresholds of pitch modulation. The distance between the threshold value and zero mean was determined by calculating confidence intervals for the expected mean values of zero by using the variance of the observed data.