PURPOSE: to evaluate the phonological working memory abilities and check possible influences of impulsivity in patients starting treatment at the program for Alcohol and Drug users at CAISM. METHOD: 29 patients: 21 males and 8 females, drug users, 37.9±10.5 year old and with 10.59±3.53 years of schooling; and 30 volunteers: 19 males and 11 female, 32.4±11.9 year old and 11.07±3.29 years of schooling, with no psychiatric history or substance abuse freely participated. The subjects were asked to attend the specific evaluation, aiming to assess: 1) phonological working memory for words and pseudowords, 2) impulsivity in its second order factors (attention impulsiveness, motor and non-planning). RESULTS: concerning the performance of the subjects in the drug users' group in the evaluation of phonological working memory when compared to the control group we found a reduction in both the auditory word span and pseudowords, as well as the total number of correct recalls of words and pseudowords. In the evaluation of impulsivity, the group of drug users had high scores comparing to control subjects in all subtypes related to impulsivity, including the total score of impulsivity. There were no correlations among impulsivity scores and words and/or pseudowords' span. CONCLUSION: this pattern of responses indicates impairment in verbal working memory processing and high level of impulsivity in this population of chronic drug users. The poor performance of chronic drug users on all tests of phonological working memory is probably not due to the increased noted impulsivity. These analyses help to plan treatment strategies intended towards the detected alterations.