Background: Few studies have examined the risk factors among Iranians attempting suicide. Objectives: The present study aimed to explore the risk factors of suicide among patients admitted to hospitals due to suicide attempts. Patients and Methods: Suicidal participants (N = 200, 104 males and 96 females, aged 18 to 40) were recruited via judgmental sampling method, and non-suicidal participants (n = 300, 166 males and 134 females, aged from 18 to 40) were selected via a convincing sampling method. They completed a battery of questionnaires on family strength, religious identification, substance use, hopelessness, depression, sexual, emotional, and physical abuse, impulsive aggression, neuroticism, suicidal ideation, family discord, stressful life events, and anxiety. Results: The current use of cigarettes/hookah, lifetime non-prescribed medication use, suicidal ideation (suicidal thoughts/tendencies), and depression significantly predicted suicide attempts. In addition, lower levels of religious belief were significantly associated with a higher likelihood of attempting suicide. Conclusions: Suicide prevention programs should explore the efficacy of treating individuals with substance abuse disorders, depression, and suicidal thoughts/tendencies for the reduction of suicide attempts. Furthermore, family, media, and school-based programs to internalize religious values would be valuable components of prevention programs for suicide in Iran.