Abstract: Background and Objective: Pollen morphology is one of the significant tools in solving some taxonomic problems on the family, generic or specific level and has become part of the multidisciplinary and collaborative approach in plant systematic and evolution. Therefore, this study aimed to investigate and describe the pollen morphology of 10 species belongs to 9 genera and five tribes of Brassicaceae from eastern region of Saudi Arabia by using light and scanning electron microscope. Materials and Methods: To study the pollen morphology for ten species representing 9 genera and 5 tribes of Brassicaceae the Light Microscope (LM) and Scanning Electron Microscope (SEM). For the SEM the pollen was placed directly on brass stubs without treatment and mounted onto a metallic stub with a double-sided adhesive tape. Gold coating of few nanometers was applied using sputter coating machine (Quorum, Q150R ES, UK) to avoid charging and capture high quality images. Two statistical program; PRIMER 6, version 6.1.6 and SPSS version 16are used to fine the relationships among the studied species. Results: The shape of pollen grains recorded three types; prolate, subprolate and prolate-spheroidal, the main types were prolate. The apertures were tricolpate in all studied species. Exine ornamentation of studied species recorded two types; reticulate and coarsely reticulate. The results of numerical analysis showed that species were grouped into two major clusters and each cluster divided into two groups. Conclusion: The results show that the morphology of pollen grains cannot be useful for taxonomical classification of the tribes but can be useful for differentiate between species belong to the same genera.