Neurocognitive impairment is a well-documented consequence of long-term, repeated cocaine exposure and has been identified as an important target of treatment. Thus, this study sought to determine whether the N-methyl-d-aspartate (NMDA) partial agonist, d-cycloserine could improve neurocognitive performance in a sample of 27 long-term, high dose cocaine dependent individuals who were not seeking treatment at the time of enrollment in the study. This double-blind, placebo-controlled study evaluated whether a single dose of 0 or 50 mg of d-cycloserine would enhance performance on measures of attention/information processing speed, episodic memory, and executive/frontal lobe functioning relative to test performance at baseline. The results revealed that d-cycloserine did not modulate neurocognition in this cohort, though there are a number of factors that may have mitigated the effects of d-cycloserine in this particular study. The negative findings notwithstanding, the current study serves as a springboard for future investigations that will examine whether other medications that can modulate neurocognition in cocaine-dependent study participants.