Introduction: In this paper, Spanish future primary teachers' pedagogical knowledge of numbers and operation, as revealed through their results in the TEDS-M ("Teacher Education and Development Study in Mathematics"), is compared with that of two other groups. The first group are the future primary teachers of other OECD countries that also participated in the study: Norway, Germany, Chile and Poland. The second group are the future primary teachers of participating countries where preservice teachers receive training similar to Spain's teacher training, namely, China-Taipei, Singapore, United States, Philippines and Switzerland. Method: To meet this objective, data was analyzed and parameters were calculated based on categories that characterize the pedagogical knowledge required to correctly answer the questions in this conceptual domain, using response assessment criteria. Results: We found that Spanish prospective teachers have lower results, in general, than those of the other OECD countries and of countries in the group with similar training programs. The Spanish scores are lower than Norwegian, Swiss and Singaporean scores in all aspects considered. For most categories, Spain obtained higher scores than Philippines and Chile, and similar scores to the U.S.A. Discussion: When comparing the results from the OECD countries that participated in the two international studies, TEDS-M and TIMSS 2011 (Spain, Poland, USA, Norway, Germany and Chile), we find that their relative positions are maintained in the ranking of assessed mathematical knowledge of numbers and operations, whether in preservice teachers or in primary students. Spanish results in the TIMSS are just above Poland and Chile and below the rest. The results obtained in this study may be useful in the current syllabus design process for subjects in the Elementary Teacher Education degree.