---

Background and Objective: Acquired immunodeficiency syndrome (AIDS) is a definition of dysfunction of immune system in human that is induced by infection with a virus named human immunodeficiency virus (HIV). The most high risk group in HIV infected people are intravenous drug users (IDUs) with unsafe sex. This study was conducted to evaluate knowledge and attitude of IDUs with unsafe sex about AIDS and relation with socioeconomic levels in Golestan province in North of Iran. Materials and Methods: This Cross-Sectional study was conducted on 134 IDUs in Golestan province during 2007. Samples were chosen by a random systematic method. Data was collected with interview by standard questionnaire. Data was analyzed by SPSS-16 and One-way ANOVA,T-test student, Kruskal-wallis, Mann-Whitney U and Kendall tests. Results: This study showed that 36.6% of samples had moderate knowledge about AIDS and 49.3% of them had negative attitude about AIDS. 67% of subjects had education between 6-12 years, 44.8% were married and 53% were jobless and without income. Level of knowledge had a significant relation with age (P<0.05) and education level (P<0.05). Older subjects had better knowledge. Level of knowledge in 25-34 years group was higher than other age. Well educated people had higher knowledge compared with low educated and illitrate subjects. Level of knowledge had a significant relation with attitude (P<0.05). Conclusion: The findings of this study showed that 65% of subjects with high risk behavior on HIV/AIDS had a appropriate knowledge about transmission of HIV, but half of these population have a poor HIV/AIDS attitude.