Pitch discrimination interference (PDI) is an impairment in fundamental frequency (F0) discrimination between two sequentially presented complex (target) tones produced by another complex tone (the interferer) that is filtered into a remote spectral frequency region. Micheyl and Oxenham [J. Acoust. Soc. Am. 121, 1621-1631 (2007)] reported a modest PDI for target tones and interferers both containing resolved harmonics when the F0 difference between the two target tones (DeltaF0) was small. When the interferer was in a lower spectral region than the target, a much larger PDI was observed when DeltaF0 was large (14%-20%), and, under these conditions, performance in the presence of an interferer was worse than at smaller DeltaF0s. The present study replicated the occurrence of PDI for complex tones containing resolved harmonics for small DeltaF0s. In contrast to Micheyl and Oxenham's findings, performance in the presence of an interferer always increased monotonically with increasing DeltaF0. However, when the interferer was in a lower spectral region than the target (and not vice versa), some subjects needed verbal instructions or modified stimuli to choose the correct cue, indicating an asymmetry in spontaneous obviousness of the correct listening cue across conditions.