Solitary subterranean rodents with a low frequency of direct contact between conspecifics are expected to use chemical communication to coordinate social and reproductive behavior. We examined whether reproductive tuco-tucos (Ctenomys talarum) were able to discriminate the reproductive condition, sex, and source population of conspecifics by means of chemical cues contained in urine, feces, soiled shavings, or anogenital secretions. During preference tests in which animals had direct contact with these chemical cues, tuco-tucos were able to determine the reproductive condition of opposite sex conspecifics independent of the source of odor. When only olfactory cues were available, both sexes discriminated reproductive condition of opposite sex individuals using urine. Females were also able to discriminate the reproductive condition of males using soiled shavings. Females spent more time investigating male odors than female odors; except in the case of feces, breeding males spent similar amounts of time investigating male and female odors. No preferences were detected for opposite sex urine from members of an animal's own versus another population. The role of chemical cues in territory defense and breeding performance by this highly territorial subterranean rodent is discussed.