The effect of stimulus duration on the detection of sinusoids added to continuous pedestals was investigated in two studies. Gated 1000-Hz sinusoids were added in phase with continuous pedestals in the presence of a steady background noise at durations between 10 and 500 msec. Plots of signal intensity necessary for approximately 75%-correct detections as a function of duration revealed enhanced detectability and an intensity duration reciprocity factor of 14 dB per log unit of time. In the second experiment, signal energy was held constant as duration of the probe was varied between 10 and 100 msec, and the proportion of correct responses was measured in a two-interval forced-choice procedure. Marked improvement in detectability obtained as signal duration was increased. When increment energy was held constant, discriminability remained unchanged in the face of a 10-dB decrease in signal energy. After correcting an energy-detection model for internal noise, the model accurately predicted the proportion of correct responses. Finally, it is argued that a description of detection data in terms of increment energy renders results obtained with pedestals simpler and more understandable.