This article analyses the structure of Yoruba numerals and their derivation. Data are collected from the compilation of Yoruba numerals and observation of its use coupled with the researcher's intuitive knowledge of the language. The work dwells on the existing literature on numerals too. The author adopts a descriptive method in analysing the data. The work looks at the roles of affixes in realising odd numbers, multiples of 20, centenary, bicentenary, and so on in their order of increase. It is discovered that the direction of counting in Yoruba is largely progressive. Besides, the language adopts base 5, decimal (base 10) and vigesimal (base 20) systems of counting. It is equally discovered that the choice of either of the two variations is largely dependent on the articulatory parameter of the first vowel (V1) of the root word. It is noted that the Yoruba numeral system offers a suitable linguistic database for both the theoretical and empirical domains of linguistic study especially documentary linguistics. The current study has general pedagogic implications for the teaching and learning of Yoruba numerals.