This study aimed to assess the existence of differences of parental bonding styles in two groups of 100 male participants, with ages raging from 19 to 48, in Algarve, Portugal. The first group, Group-T, was composed by drug addicted individuals engaged in treatment; the second group, Group-NT, was composed by volunteers who did not refer use or abuse of heroin and cocaine. The instrument employed was the Portuguese version of the PBI - Parental Bonding Instrument (Baptista, 1993). There were no significant differences concerning the socioeconomic level of the mothers and fathers of the participants of both groups. We concluded that there were statistically significant differences between the two groups concerning the parental bonding styles, where Group-T presented a greater prevalence of “affection control” responses, in contrast to the results of Group-NT, which presented a greater prevalence of “optimal connection”.