Background: The aim of this study was to develop the Pencil Pain Scale as a new one-dimensional scale for evaluating pain in school-age children (6-12 years old).Methods: The population of this study is composed of 6-12 year-old children who gave blood for examination rather than for an acute or severe cause. The research sample included randomly selected children (N= 464) who applied to the blood collection units of a state hospital between November 2017 - February 2018, on three days of the week (Monday, Wednesday, Friday).A questionnaire that specifies the characteristics of children, the newly developed Pencil Pain Scale, and the two widely used scales (Visual Analogue Scale and the Facial Expressions Rating Scale) were used to collect data. The data obtained were analyzed with percentage distributions, mean, chi-square, t-test, ANOVA, Kruskal Wallis, Mann Whitney U test and correlation. Ethical principles were followed in the study.Results: According to expert opinions, it was determined that the Pencil Pain Scale had content validity (Content Validity Index= +1.00). It was found that the scale made measurements similar to a previously conducted study and had convergent validity. Also, the scale was found to be sensitive enough to distinguish the differences and to be reliable (p<.001). It was also found that the Pencil Pain Scale performs measurements that are in agreement with the Visual Analog Scale and the Facial Expression Rating Scale and has parallel form reliability (p>.05). The Pencil Pain Scale was developed in a valid and reliable way. Conclusion: The Pencil Pain Scale is a valid and reliable scale. In order to make the Pencil Pain Scale a standard scale for measuring children's pain, it needs to be used in different studies and age groups with different scales for different pain types.