This study aims to determine pre-service preschool teachers' opinions about writing to learn mathematics and the methods they use while writing. Survey design, one of the quantitative research methods, was used in the study. The sample of the study consisted of a total of 418 pre-service teachers studying in the preschool teaching undergraduate program of six different state universities. The Likert-type questionnaire developed by Ozturk and Gunel (2015) was used to collect data. Frequency analysis, Mann-Whitney U test and one-way analysis of variance (ANOVA) were used in data analysis. According to the results obtained from the study, it was determined that pre-service preschool teachers used revising writing and planned writing processes when the methods they used while writing about learning mathematics were taken into consideration. When this situation is evaluated, it can be said that the pre-service teachers carried out a comprehensive writing process. On the other hand, no significant difference was found between pre-service teachers' thoughts about writing to learn mathematics and their gender and grade level. In addition, although there was no significant difference between pre-service teachers' opinions about the methods they used while writing to learn mathematics and their grade levels, a significant difference was found according to the gender variable.