This study was performed to determine the effect of several preintervention preparation practices on pain and anxiety related to the peripheral cannulation procedure in children ages 9-12 years. The study included 60 Turkish children (28 female, 32 male, randomly selected by lot), 30 of whom were included in the intervention group and 30 of whom were included in the control group. The children's demographic data were collected by a data collection form prepared by the researcher. The children in the intervention group read the training manual before peripheral cannulation, and the procedure was demonstrated on a teddy bear. Their level of pain was assessed using the Wong-Baker Faces Rating Scale, and their level of anxiety was determined by the Spielberger State-Trait Anxiety Inventory for Children, before and during the procedure in both groups. Results showed that while anxiety and pain scores increased during the actual procedure compared to the preparatory procedure in the control group (anxiety t = -4.957, pain Za = -4.048), anxiety and pain scores decreased during the actual procedure in the intervention group compared to the preparatory procedure (anxiety t = 7.896, pain t = 6.196). When the pain and anxiety scores were examined, it was found that both anxiety and pain scores in the intervention group were significantly lower than in the control group. In conclusion, children in this study experienced pain and situational anxiety during peripheral cannulation, and this pain can be reduced by preparing the child in advance of the procedure. It is suggested that children should be informed about and able to practice the procedure on a toy or model before peripheral cannulation. Preparation of the children to painful procedures in accordance with their cognitive development can reduce anxiety and pain.