Dissertation (MSc Mental Health Nursing)Background: There is a significant increase of drug abuse especially injection in Tanzania. Injection behaviors have been known to facilitate the transmission of HIV. Injecting drug users are among the population with an increased risk of contracting HIV. Understanding their perceived risk is a significant factor in determining the behaviors of this group Objective: This study wanted to assess the perceived risk of HIV infections among injecting drug users in Zanzibar. Methods: A cross-sectional study design was conducted among 1308 injecting drug users in Zanzibar by using quantitative approach. Multistage sampling was used and written questionnaires were employed for data collection Descriptive statistics were calculated using the demographic data and data on high risk injection behaviors. A chi-squared test was done to observe the relation between independent and dependent variable as well univariate analysis was done to identify the predictor variables. Finally a multiple logistic regression was employed to identify the independent effects, from the perceived risk of HIV infection among injecting drug users. Results: This study found about 49.5% perceived low risk of HIV infection The best five predictors includes the period of drug using of between 4-10 years which were more likely to perceive a low risk of HIV infection (AOR:1.532,95% CI 1.004-2.338), preference for amphetamine as the drug of choice were more likely to perceive low risk of HIV infection (AOR:2.526,95%CI 1.527-4.179),site of injection such as hands and foot were less likely to perceive low risk of HIV infection(AOR: 0.393 95% CI 0.198- 0.778),low frequency of using drug were more likely to perceive a low risk of HIV infection (AOR:2.330 95% CI 1.402-3.874) and injecting drug, own a room alone were less likely to perceive a low risk of HIV infection (AOR:0.496, 95% CI 0.335-0.734). Conclusion: We find that lower perceived risk of HIV infection are associated with a less period of using drug , preferred drug type, site of injection), frequency of using drug and place for injecting drug. This risk perception should be taken in to consideration when studying the risk of HIV infection among injection drug users. These findings could help to better target and focus interventions and understand the negative effects of fear arousing intervention as part of HIV prevention in Zanzibar.