ABSTRACTAn experiment was performed to test the effect of changing the CS‐US interval on the pattern of conditioned salivation. Each of 6 subjects (Ss) received 60 reinforced trials on each of 3 CS‐US intervals: 10, 20, and 40 sec. For each CS‐US interval 10 test trials were given to determine the change in pattern of response with change in the CS‐US interval. An additional session included 2 test trials in which an extraneous stimulus was given simultaneously with the CS. The results showed little evidence of inhibition of delay in the longer intervals or of disinhibition when the extraneous stimulus was applied. The most significant result was a response which followed CS offset in the 20‐ and 40‐sec intervals. The question of the nature of this response remains to be answered by use of a different experimental design. Significance of the level of conditioning remained high (p<. 00001) over the manipulation of CS