Different methods of poisoning used by individuals with the diagnosis of parasuicide admitted to the Loghman Hospital, Tehran, from 2000 to 2004 were investigated, with particular focus on gender and age differences. Drugs, pesticides, and other agricultural chemicals (women: 12.7%, men: 9%) were the most commonly used methods. In males, the percentage of use of drugs increased with age, but the frequency of pesticides use decreased with age. In females, drugs were most often used in the youngest age group, whereas the use of pesticides was lowest in the youngest age category. Females outnumbered males, especially in the youngest age group of 10 to 19 years olds. Drugs and pesticides were the substances used most often for parasuicide in each age group regardless of gender.