Family-related factors play a crucial role in the onset, development, and maintenance of drug misuse and addiction. To investigate the hypothesis that families with a cocaine addicted son display more dysfunction than control families, we applied the Personal Authority in the Family System and the Self-Report Measure of Family Functioning to 67 case triads (child-father-mother) in which the son was an inpatient with a primary diagnosis of cocaine abuse or dependence and to 67 matched control triads from the community (Pelotas, Brazil) in 2000. Case children, mothers, and fathers were significantly more likely to present nuclear family triangulation than their matched control subjects. In addition, case triads had a significantly greater chance of perceiving family functioning as enmeshment. These results suggest both structural and functional differences in these families. We argue for the need of interventions in the family as a whole and for further research in this area.